diff --git a/.crow/retire-slot.yaml b/.crow/retire-slot.yaml
new file mode 100644
index 0000000..1b62ba7
--- /dev/null
+++ b/.crow/retire-slot.yaml
@@ -0,0 +1,72 @@
+# Delete a retired slot's objects from the bucket.
+#
+# The config half is a commit, so it runs on a workstation:
+#   just retire-slot <codename> --apply
+#
+# This half needs the B2 credentials, which only exist in CI.
+# `local/retire-slot.R` refuses any slot still listed in `local.rpkgs_slots`,
+# so this cannot delete a live slot. Both architectures go together.
+#
+# Dry run unless RETIRE_APPLY is 'yes':
+#
+#   crow pipeline create devxy/build-cran-binaries --branch main \
+#     --var retire_slot=alpine322 --var RETIRE_APPLY=yes
+
+variables:
+  # A manual pipeline creation instantiates every file in .crow/, so the
+  # default must be a value the script never accepts.
+  retire_slot:
+    description: "Codename of the slot to retire (e.g. alpine322), or 'none'."
+    default: none
+  RETIRE_APPLY:
+    description: "Set to 'yes' to delete. Anything else reports and changes nothing."
+    options:
+      - 'no'
+      - 'yes'
+    default: 'no'
+
+when:
+  - event: manual
+    evaluate: 'retire_slot != "none"'
+
+skip_clone: true
+
+labels:
+  group: rpkgs-amd64
+
+steps:
+  - name: 'Delete the retired slot from the bucket'
+    image: reg.devxy.io/rpkgs/build-env-alpine:3.24
+    pull: true
+    environment:
+      OTEL_R_TRACES_EXPORTER: none
+      OTEL_R_LOGS_EXPORTER: none
+      OTEL_R_METRICS_EXPORTER: none
+      B2_S3_ACCESS_KEY:
+        from_secret: B2_S3_ACCESS_KEY
+      B2_S3_SECRET_KEY:
+        from_secret: B2_S3_SECRET_KEY
+      REPO_RO_TOKEN:
+        from_secret: REPO_RO_TOKEN
+      R_LIBS_USER: /tmp/R-pkgs
+      # Pipeline variables are substituted into the YAML, not exported, so they
+      # have to be bound here to be readable as env vars in the script below.
+      RETIRE_SLOT: ${retire_slot}
+      RETIRE_APPLY: ${RETIRE_APPLY}
+    commands:
+      - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
+      - mkdir -p /tmp/R-pkgs
+      - /opt/R/4.5.3/bin/Rscript local/install-bincraft.R
+      - |
+        set -eu
+        APPLY=""
+        if [ "$$RETIRE_APPLY" = "yes" ]; then
+          APPLY="--apply"
+        fi
+        /opt/R/4.5.3/bin/Rscript local/retire-slot.R "$$RETIRE_SLOT" --assets-only $$APPLY
+    backend_options:
+      docker:
+        resources:
+          requests:
+            memory: 2Gi
+            cpu: 1000m
diff --git a/README.md b/README.md
index 989069e..d137728 100644
--- a/README.md
+++ b/README.md
@@ -198,6 +198,28 @@ Example: <https://cran.devxy.io/arm64/rhel9/latest>
 
 Technically, no date-based snapshots are planned, so this component from the Posit PM structure is not included.
 
+## Retiring a slot
+
+A slot is only reachable if it is listed in `local.rpkgs_slots` in `cdn.tf`, which feeds `UNION_SLOTS` in `edge/rpkgs-router.ts`.
+An unrouted slot serves the flat index to every client, so its binaries fail at `dyn.load()` under every R minor but one.
+
+In order:
+
+1. Remove it from `local.rpkgs_slots` in `cdn.tf` and from `DistroId` in the website's `src/src/data/repos.ts`, then `tofu apply`.
+2. `just retire-slot <codename> --apply`, then commit.
+3. Delete its cron jobs on the Crow server; `local/retire-slot.R` prints them with the API call.
+4. Delete its objects:
+
+   ```sh
+   crow pipeline create devxy/build-cran-binaries --branch main \
+     --var retire_slot=<codename> --var RETIRE_APPLY=yes
+   ```
+
+Steps 2 and 4 refuse any slot still listed in `cdn.tf`.
+Running step 4 before step 2 means the next nightly rebuilds everything just deleted.
+
+`just check-slots` fails when a pipeline still targets an unrouted slot.
+
 ## Helpers
 
 Helper scripts are located in `local/`.
diff --git a/justfile b/justfile
index 6c75b13..36ad0e1 100644
--- a/justfile
+++ b/justfile
@@ -87,3 +87,11 @@ edge-test:
         denoland/deno:latest \
         deno test -A edge/rpkgs-router.test.ts
     fi
+
+# fail if any pipeline still targets a slot the edge does not route
+check-slots:
+    Rscript local/check-slots.R
+
+# strip a retired slot from .crow/*.yaml (dry run; pass --apply to write)
+retire-slot codename *flags:
+    Rscript local/retire-slot.R {{ codename }} --config-only {{ flags }}
diff --git a/local/check-slots.R b/local/check-slots.R
new file mode 100644
index 0000000..5345da9
--- /dev/null
+++ b/local/check-slots.R
@@ -0,0 +1,151 @@
+### Fail when a pipeline targets a slot that is not in `local.rpkgs_slots`.
+#
+#   Rscript local/check-slots.R
+#
+# That list feeds `UNION_SLOTS`, which `edge/rpkgs-router.ts` gates per-R-minor
+# routing on. An unrouted slot serves the flat index to every client, so its
+# binaries fail at dyn.load() under every R minor but one.
+#
+# One-directional: a published slot missing from some pipeline is only
+# reported, since several pipelines cover a subset on purpose.
+
+options(error = function() {
+  cat("ERROR:", geterrmessage(), "\n", file = stdout())
+  q(status = 1)
+})
+
+# Parses the distro list out of the setproduct's second array.
+published_codenames <- function(path = "cdn.tf") {
+  if (!file.exists(path)) {
+    stop(
+      sprintf("%s not found; run this from the repository root.", path),
+      call. = FALSE
+    )
+  }
+  lines <- readLines(path, warn = FALSE)
+  start <- grep("rpkgs_slots\\s*=", lines)
+  if (length(start) != 1L) {
+    stop(
+      "Could not find exactly one `rpkgs_slots` local in cdn.tf.",
+      call. = FALSE
+    )
+  }
+  block <- paste(lines[start:min(start + 10L, length(lines))], collapse = "\n")
+  arrays <- regmatches(block, gregexpr("\\[[^]]*\\]", block))[[1L]]
+  if (length(arrays) < 2L) {
+    stop(
+      "`rpkgs_slots` no longer has the two-array setproduct shape this parses.",
+      call. = FALSE
+    )
+  }
+  codenames <- gsub(
+    '"',
+    "",
+    regmatches(arrays[[2L]], gregexpr('"[^"]+"', arrays[[2L]]))[[1L]]
+  )
+  if (length(codenames) == 0L) {
+    stop("Parsed an empty distro list from cdn.tf.", call. = FALSE)
+  }
+  codenames
+}
+
+UBUNTU_CODENAMES <- c(
+  resolute = "ubuntu-2604",
+  noble = "ubuntu-2404",
+  jammy = "ubuntu-2204"
+)
+
+as_pipeline_os <- function(codename) {
+  ifelse(
+    codename %in% names(UBUNTU_CODENAMES),
+    UBUNTU_CODENAMES[codename],
+    ifelse(
+      grepl("^rhel[0-9]+$", codename),
+      sub("^rhel", "redhat-", codename),
+      ifelse(
+        grepl("^alpine[0-9]+$", codename),
+        sub("^alpine([0-9])([0-9]+)$", "alpine-\\1\\2", codename),
+        NA_character_
+      )
+    )
+  )
+}
+
+# Structural lines only, so a codename in a comment is not a finding.
+slots_in_pipeline <- function(path) {
+  lines <- readLines(path, warn = FALSE)
+  row <- regmatches(
+    lines,
+    regexec("^\\s*-?\\s*(OS|CODENAME|OS_ID):\\s*(\\S+)\\s*$", lines)
+  )
+  opt <- regmatches(
+    lines,
+    regexec("^\\s*-\\s*([a-z0-9]+-[a-z0-9]+)-(amd64|arm64)\\s*$", lines)
+  )
+  hits <- c(
+    vapply(
+      row,
+      function(m) if (length(m) == 3L) m[[3L]] else NA_character_,
+      ""
+    ),
+    vapply(opt, function(m) if (length(m) == 4L) m[[2L]] else NA_character_, "")
+  )
+  hits <- hits[!is.na(hits)]
+  # `OS: alpine` (build-all-versions' bare image name) is not a slot.
+  unique(hits[grepl("^(alpine|redhat|ubuntu)-?[0-9]", hits)])
+}
+
+codenames <- published_codenames()
+published_os <- unname(as_pipeline_os(codenames))
+if (anyNA(published_os)) {
+  stop(
+    sprintf(
+      "Unrecognised codename(s) in cdn.tf: %s",
+      paste(codenames[is.na(published_os)], collapse = ", ")
+    ),
+    call. = FALSE
+  )
+}
+# Files spell a slot either way, so accept both.
+published <- unique(c(published_os, codenames))
+
+cat(sprintf(
+  "Published slots (cdn.tf): %s\n\n",
+  paste(sort(published_os), collapse = ", ")
+))
+
+files <- sort(list.files(".crow", pattern = "\\.yaml$", full.names = TRUE))
+findings <- list()
+for (f in files) {
+  stale <- setdiff(slots_in_pipeline(f), published)
+  if (length(stale) > 0L) {
+    findings[[f]] <- stale
+    cat(sprintf(
+      "%-45s targets unpublished: %s\n",
+      f,
+      paste(sort(stale), collapse = ", ")
+    ))
+  }
+}
+
+uncovered <- setdiff(
+  published_os,
+  unique(unlist(lapply(files, slots_in_pipeline)))
+)
+if (length(uncovered) > 0L) {
+  cat(sprintf(
+    "\nNote: %s appear(s) in no pipeline at all.\n",
+    paste(sort(uncovered), collapse = ", ")
+  ))
+}
+
+if (length(findings) == 0L) {
+  cat("All pipeline slots are published and routed.\n")
+  quit(status = 0)
+}
+
+cat(sprintf(
+  "\n%d file(s) target an unrouted slot. Retire it with:\n  just retire-slot <codename>\n",
+  length(findings)
+))
+quit(status = 1)
diff --git a/local/retire-slot.R b/local/retire-slot.R
new file mode 100644
index 0000000..383fd2c
--- /dev/null
+++ b/local/retire-slot.R
@@ -0,0 +1,240 @@
+### Retire a slot: strip it from the pipelines and delete its objects from S3.
+#
+#   Rscript local/retire-slot.R <codename> [--apply] [--config-only|--assets-only]
+#
+# Retiring a distro retires both architectures, because `local.rpkgs_slots` in
+# `cdn.tf` is a setproduct over them.
+#
+# Order: remove the slot from `local.rpkgs_slots` (and the website's
+# `DistroId`) and apply that first, then run this. Deleting objects while a
+# pipeline still targets the slot just means the next nightly rebuilds them.
+#
+# Cron jobs live on the Crow server, not here, and are printed at the end.
+#
+# Only structural YAML is edited. Prose mentioning the slot is left alone, so
+# grep for the name afterwards.
+#
+# Dry run by default.
+
+options(error = function() {
+  cat("ERROR:", geterrmessage(), "\n", file = stdout())
+  q(status = 1)
+})
+
+args <- commandArgs(trailingOnly = TRUE)
+apply_changes <- "--apply" %in% args
+config_only <- "--config-only" %in% args
+assets_only <- "--assets-only" %in% args
+args <- args[!args %in% c("--apply", "--config-only", "--assets-only")]
+if (length(args) != 1L || (config_only && assets_only)) {
+  stop(
+    "usage: retire-slot.R <codename> [--apply] [--config-only|--assets-only]",
+    call. = FALSE
+  )
+}
+codename <- args[[1L]]
+
+# The bucket and `CODENAME:` say `alpine322`; `OS:` and the options say
+# `alpine-322`. Both have to go.
+pipeline_os <- if (grepl("^rhel[0-9]+$", codename)) {
+  sub("^rhel", "redhat-", codename)
+} else if (grepl("^alpine[0-9]+$", codename)) {
+  sub("^alpine", "alpine-", codename)
+} else {
+  # Single bracket so an unknown codename yields NA, not an error.
+  c(resolute = "ubuntu-2604", noble = "ubuntu-2404", jammy = "ubuntu-2204")[
+    codename
+  ]
+}
+if (is.na(pipeline_os) || length(pipeline_os) == 0L) {
+  stop(sprintf("Unrecognised codename '%s'.", codename), call. = FALSE)
+}
+
+# The `OS_VERSION` dropdowns are keyed on the image tag, not the slot name.
+image_tag <- if (grepl("^alpine-", pipeline_os)) {
+  sub("^alpine-([0-9])([0-9]+)$", "\\1.\\2", pipeline_os)
+} else if (grepl("^redhat-", pipeline_os)) {
+  sub("^redhat-", "", pipeline_os)
+} else {
+  codename
+}
+
+# Refuse a slot that is still routed: deleting its objects would leave the edge
+# serving indexes that name files which no longer exist.
+tf <- readLines("cdn.tf", warn = FALSE)
+start <- grep("rpkgs_slots\\s*=", tf)
+if (length(start) != 1L) {
+  stop(
+    "Could not find exactly one `rpkgs_slots` local in cdn.tf.",
+    call. = FALSE
+  )
+}
+block <- paste(tf[start:min(start + 10L, length(tf))], collapse = "\n")
+if (grepl(sprintf('"%s"', codename), block, fixed = TRUE)) {
+  stop(
+    sprintf(
+      "'%s' is still listed in `local.rpkgs_slots` in cdn.tf, so the edge still routes it. Remove it there (and from the website's DistroId union) and apply the OpenTofu change first.", # nolint
+      codename
+    ),
+    call. = FALSE
+  )
+}
+
+cat(sprintf(
+  "Retiring %s (pipelines call it '%s', images tag it '%s')\n\n",
+  codename,
+  pipeline_os,
+  image_tag
+))
+
+## 1. Pipeline definitions ----------------------------------------------------
+
+# Line-based on purpose: a YAML round trip would reflow all 18 files.
+strip_slot <- function(lines) {
+  keep <- rep(TRUE, length(lines))
+  i <- 1L
+  while (i <= length(lines)) {
+    line <- lines[[i]]
+    row <- regexec(
+      sprintf(
+        "^(\\s*)-\\s*(OS|CODENAME):\\s*(%s|%s)\\s*$",
+        pipeline_os,
+        codename
+      ),
+      line
+    )
+    m <- regmatches(line, row)[[1L]]
+    if (length(m) == 4L) {
+      indent <- nchar(m[[2L]])
+      keep[[i]] <- FALSE
+      j <- i + 1L
+      while (j <= length(lines)) {
+        nxt <- lines[[j]]
+        if (
+          !nzchar(trimws(nxt)) || nchar(sub("^(\\s*).*$", "\\1", nxt)) <= indent
+        ) {
+          break
+        }
+        keep[[j]] <- FALSE
+        j <- j + 1L
+      }
+      i <- j
+      next
+    }
+    if (grepl(sprintf("^\\s*-\\s*%s-(amd64|arm64)\\s*$", pipeline_os), line)) {
+      keep[[i]] <- FALSE
+    }
+    if (grepl(sprintf("^\\s*-\\s*'%s'\\s*$", image_tag), line)) {
+      keep[[i]] <- FALSE
+    }
+    i <- i + 1L
+  }
+  out <- lines[keep]
+  # A dropdown cannot default to an option that no longer exists.
+  bad_default <- grepl(sprintf("^\\s*default:\\s*'%s'\\s*$", image_tag), out)
+  if (any(bad_default)) {
+    for (k in which(bad_default)) {
+      opts <- grep("^\\s*-\\s*'[^']+'\\s*$", out[seq_len(k - 1L)])
+      if (length(opts) == 0L) {
+        next
+      }
+      # Walk back to this block's first option, not the nearest one.
+      first <- max(opts)
+      while (first > 1L && grepl("^\\s*-\\s*'[^']+'\\s*$", out[[first - 1L]])) {
+        first <- first - 1L
+      }
+      replacement <- sub("^\\s*-\\s*'([^']+)'\\s*$", "\\1", out[[first]])
+      out[[k]] <- sub("'[^']+'", sprintf("'%s'", replacement), out[[k]])
+      cat(sprintf("  default moved to '%s'\n", replacement))
+    }
+  }
+  out
+}
+
+if (!assets_only) {
+  files <- sort(list.files(".crow", pattern = "\\.yaml$", full.names = TRUE))
+  touched <- 0L
+  for (f in files) {
+    lines <- readLines(f, warn = FALSE)
+    out <- strip_slot(lines)
+    if (length(out) == length(lines)) {
+      next
+    }
+    touched <- touched + 1L
+    cat(sprintf(
+      "  %s %-45s -%d lines\n",
+      if (apply_changes) "EDIT   " else "would edit",
+      f,
+      length(lines) - length(out)
+    ))
+    if (apply_changes) {
+      writeLines(out, f)
+    }
+  }
+  if (touched == 0L) {
+    cat("  No pipeline references the slot.\n")
+  } else if (apply_changes) {
+    cat(sprintf(
+      "  %d file(s) edited. Verify with `crow lint .crow/` and `Rscript local/check-slots.R`.\n",
+      touched
+    ))
+  }
+  cat("\n")
+}
+
+## 2. Bucket objects ----------------------------------------------------------
+
+if (!config_only) {
+  library(s3fs, quietly = TRUE)
+  if (!nzchar(Sys.getenv("B2_S3_ACCESS_KEY"))) {
+    stop(
+      "B2_S3_ACCESS_KEY is unset. B2 lists nothing without credentials, which is indistinguishable from an already-clean slot.", # nolint
+      call. = FALSE
+    )
+  }
+  bucket <- "devxy-rpkgs-binaries"
+  s3fs::s3_file_system(
+    aws_access_key_id = Sys.getenv("B2_S3_ACCESS_KEY"),
+    aws_secret_access_key = Sys.getenv("B2_S3_SECRET_KEY"),
+    endpoint = "https://s3.eu-central-003.backblazeb2.com",
+    region_name = "eu-central-003",
+    refresh = TRUE
+  )
+
+  for (arch in c("amd64", "arm64")) {
+    prefix <- sprintf("%s/%s/%s", bucket, arch, codename)
+    if (!s3fs::s3_dir_exists(prefix)) {
+      cat(sprintf("  %s/%s: nothing in the bucket.\n", arch, codename))
+      next
+    }
+    objects <- s3fs::s3_dir_ls(prefix, recurse = TRUE)
+    cat(sprintf(
+      "  %s %s/%s: %d object(s)\n",
+      if (apply_changes) "DELETE" else "would delete",
+      arch,
+      codename,
+      length(objects)
+    ))
+    if (apply_changes && length(objects) > 0L) {
+      s3fs::s3_dir_delete(prefix)
+      cat(sprintf("  deleted s3://%s\n", prefix))
+    }
+  }
+  cat("\n")
+}
+
+## 3. Crons ------------------------------------------------------------------
+
+if (!apply_changes) {
+  cat("Dry run: nothing was edited or deleted. Re-run with --apply.\n\n")
+}
+
+cat("Crons still to remove on the Crow server (they are not in this repo):\n")
+cat(sprintf(
+  "  crow-at ci.devxy.io repo cron ls devxy/build-cran-binaries | grep %s\n",
+  pipeline_os
+))
+cat("  # `crow repo cron rm` 404s here; the API base is /api/v1\n")
+cat("  eval \"$(crow-at --export ci.devxy.io)\"\n")
+cat("  curl -s -X DELETE -H \"Authorization: Bearer $CROW_TOKEN\" \\\n")
+cat("    https://ci.devxy.io/api/v1/repos/5/cron/<cron-id>\n")