diff --git a/.github/scripts/__tests__/cleanup-rust-caches.mjs b/.github/scripts/__tests__/cleanup-rust-caches.mjs
new file mode 100644
index 0000000000..59cc7f48db
--- /dev/null
+++ b/.github/scripts/__tests__/cleanup-rust-caches.mjs
@@ -0,0 +1,136 @@
+import assert from 'node:assert/strict';
+import { test } from 'node:test';
+
+import { cleanupRustCaches, supersededRustCaches } from '../cleanup-rust-caches.mjs';
+
+const now = Date.parse('2026-10-21T00:00:00Z');
+const day = 24 * 60 * 60 * 1000;
+
+function cache(id, overrides = {}) {
+  return {
+    id,
+    ref: 'refs/heads/main',
+    key: `v1-rust-test-Linux-x64-12345678-${id.toString(16).padStart(8, '0')}`,
+    version: 'archive-version',
+    created_at: new Date(now - (6 - id) * day).toISOString(),
+    last_accessed_at: new Date(now - (6 - id) * day).toISOString(),
+    size_in_bytes: 500 * 1024 ** 2,
+    ...overrides,
+  };
+}
+
+test('keeps the newest generation and expires unused older generations', () => {
+  assert.deepEqual(supersededRustCaches([cache(2), cache(1), cache(3)], now), [cache(2), cache(1)]);
+});
+
+test('preserves recently used or created entries, including the 48-hour boundary', () => {
+  for (const field of ['last_accessed_at', 'created_at']) {
+    for (const age of [0, 1, 2]) {
+      const recent = cache(1, { [field]: new Date(now - age * day).toISOString() });
+      assert.deepEqual(supersededRustCaches([recent, cache(5)], now), []);
+    }
+  }
+});
+
+test('never treats different environments, jobs, architectures, or archive formats as replacements', () => {
+  const first = cache(1);
+  for (const overrides of [
+    { key: cache(2).key.replace('12345678', '87654321') },
+    { key: cache(2).key.replace('-test-', '-lint-') },
+    { key: cache(2).key.replace('Linux-x64', 'Darwin-arm64') },
+    { version: 'different-archive-version' },
+  ]) {
+    assert.deepEqual(supersededRustCaches([first, cache(2, overrides)], now), []);
+  }
+});
+
+test('ignores PR caches, other prefixes, invalid dates, and equal creation times', () => {
+  for (const overrides of [
+    { ref: 'refs/pull/12/merge' },
+    { key: 'v1-rust-unrecognized-key' },
+    { key: cache(1).key.replace('v1-rust', 'v2-rust') },
+    { created_at: 'invalid' },
+    { last_accessed_at: 'invalid' },
+    { version: '' },
+    { created_at: cache(3).created_at },
+  ]) {
+    assert.deepEqual(supersededRustCaches([cache(1, overrides), cache(3)], now), []);
+  }
+});
+
+function fixture(snapshots, status) {
+  const calls = [];
+  let reads = 0;
+  return {
+    calls,
+    context: { ref: 'refs/heads/main', repo: { owner: 'voidzero-dev', repo: 'vite-plus' } },
+    core: { info() {} },
+    github: {
+      async paginate(method, params) {
+        calls.push({ type: 'list', params });
+        return snapshots[Math.min(reads++, snapshots.length - 1)];
+      },
+      rest: {
+        actions: {
+          getActionsCacheList() {},
+          async deleteActionsCacheById(params) {
+            calls.push({ type: 'delete', params });
+            if (status) {
+              throw Object.assign(new Error('API error'), { status });
+            }
+          },
+        },
+      },
+    },
+  };
+}
+
+test('defaults to a dry run with no writes and reports eligible bytes', async () => {
+  const f = fixture([[cache(1), cache(3)]]);
+  const result = await cleanupRustCaches(f);
+  assert.deepEqual(result, { count: 1, bytes: cache(1).size_in_bytes });
+  assert.equal(f.calls.length, 1);
+  assert.equal(f.calls[0].params.ref, 'refs/heads/main');
+  assert.equal(f.calls[0].params.per_page, 100);
+});
+
+test('rechecks candidates and deletes by ID', async () => {
+  const f = fixture([[cache(1), cache(3)]]);
+  await cleanupRustCaches(f, { dryRun: false });
+  assert.deepEqual(
+    f.calls.map((call) => call.type),
+    ['list', 'list', 'delete'],
+  );
+  assert.equal(f.calls[1].params.key, 'v1-rust-test-Linux-x64-12345678-');
+  assert.equal(f.calls[2].params.cache_id, 1);
+});
+
+test('skips entries used since the snapshot or whose replacement disappeared', async () => {
+  for (const second of [
+    [cache(1, { last_accessed_at: new Date().toISOString() }), cache(3)],
+    [cache(1)],
+    [cache(3)],
+  ]) {
+    const f = fixture([[cache(1), cache(3)], second]);
+    assert.deepEqual(await cleanupRustCaches(f, { dryRun: false }), { count: 0, bytes: 0 });
+    assert.ok(f.calls.every((call) => call.type === 'list'));
+  }
+});
+
+test('tolerates concurrent eviction but reports other API failures', async () => {
+  assert.deepEqual(
+    await cleanupRustCaches(fixture([[cache(1), cache(3)]], 404), { dryRun: false }),
+    { count: 0, bytes: 0 },
+  );
+  await assert.rejects(
+    cleanupRustCaches(fixture([[cache(1), cache(3)]], 403), { dryRun: false }),
+    /API error/,
+  );
+});
+
+test('refuses a non-main run before making API requests', async () => {
+  const f = fixture([]);
+  f.context.ref = 'refs/heads/feature';
+  await assert.rejects(cleanupRustCaches(f, { dryRun: false }), /must run on main/);
+  assert.deepEqual(f.calls, []);
+});
diff --git a/.github/scripts/cleanup-rust-caches.mjs b/.github/scripts/cleanup-rust-caches.mjs
new file mode 100644
index 0000000000..29de4180f1
--- /dev/null
+++ b/.github/scripts/cleanup-rust-caches.mjs
@@ -0,0 +1,84 @@
+const ref = 'refs/heads/main';
+const unusedMilliseconds = 48 * 60 * 60 * 1000;
+
+function family(cache) {
+  // Keep the job, OS, architecture, Rust/environment hash, and archive version
+  // separate. Only the final manifest hash can differ within one family.
+  const match =
+    /^v1-rust-.+-(?:Linux|Darwin|Windows_NT)-(?:x64|arm64)-[a-f0-9]{8}-[a-f0-9]{8}$/.exec(
+      cache.key,
+    );
+  if (cache.ref !== ref || !match || !cache.version) {
+    return undefined;
+  }
+  return `${cache.key.slice(0, -9)}:${cache.version}`;
+}
+
+export function supersededRustCaches(caches, now = Date.now()) {
+  const newest = new Map();
+  for (const cache of caches) {
+    const group = family(cache);
+    const created = Date.parse(cache.created_at);
+    if (group && created > (newest.get(group) ?? -Infinity)) {
+      newest.set(group, created);
+    }
+  }
+  const cutoff = now - unusedMilliseconds;
+  return caches.filter(
+    (cache) =>
+      Date.parse(cache.created_at) < newest.get(family(cache)) &&
+      Date.parse(cache.created_at) < cutoff &&
+      Date.parse(cache.last_accessed_at) < cutoff,
+  );
+}
+
+export async function cleanupRustCaches({ github, context, core }, { dryRun = true } = {}) {
+  // This workflow runs trusted main code with actions:write. PR caches are
+  // handled separately by the existing closed-PR job.
+  if (context.ref !== ref) {
+    throw new Error('Rust cache cleanup must run on main');
+  }
+  const list = async (key) =>
+    github.paginate(github.rest.actions.getActionsCacheList, {
+      ...context.repo,
+      ref,
+      key,
+      per_page: 100,
+      sort: 'created_at',
+      direction: 'desc',
+    });
+  const now = Date.now();
+  const candidates = supersededRustCaches(await list('v1-rust-'), now);
+  let count = 0;
+  let bytes = 0;
+  for (const candidate of candidates) {
+    if (!dryRun) {
+      // Recheck recent use and the replacement before deleting. The initial
+      // snapshot may be stale after pagination or another cleanup.
+      const current = supersededRustCaches(await list(candidate.key.slice(0, -8)), now);
+      if (!current.some((cache) => cache.id === candidate.id)) {
+        continue;
+      }
+      try {
+        await github.rest.actions.deleteActionsCacheById({
+          ...context.repo,
+          cache_id: candidate.id,
+        });
+      } catch (error) {
+        if (error.status === 404) {
+          continue;
+        }
+        throw error;
+      }
+    }
+    core.info(
+      `${dryRun ? 'Would delete' : 'Deleted'} ${candidate.key} (${candidate.size_in_bytes} B)`,
+    );
+    count++;
+    bytes += candidate.size_in_bytes;
+  }
+  core.info(
+    `${dryRun ? 'Eligible' : 'Deleted'}: ${count} caches, ${(bytes / 1024 ** 2).toFixed(1)} MiB`,
+  );
+  return { count, bytes };
+}
diff --git a/.github/workflows/cleanup-cache.yml b/.github/workflows/cleanup-cache.yml
index 72f5b067f8..6499a85241 100644
--- a/.github/workflows/cleanup-cache.yml
+++ b/.github/workflows/cleanup-cache.yml
@@ -1,11 +1,20 @@
-name: Cleanup github runner caches on closed pull requests
+name: Cleanup GitHub Actions caches
 on:
   pull_request:
     types:
       - closed
+  schedule:
+    - cron: '23 */6 * * *'
+  workflow_dispatch:
+    inputs:
+      dry-run:
+        description: Report unused main Rust caches without deleting them.
+        type: boolean
+        default: true
 
 jobs:
   cleanup:
+    if: github.event_name == 'pull_request'
     runs-on: ubuntu-latest
     permissions:
       actions: write
@@ -13,17 +22,38 @@ jobs:
       - name: Cleanup
         run: |
           echo "Fetching list of cache keys"
-          cacheKeysForPR=$(gh cache list --ref $BRANCH --limit 100 --json id --jq '.[].id')
+          cacheKeysForPR=$(gh cache list --ref "$BRANCH" --limit 100 --json id --jq '.[].id')
 
           ## Setting this to not fail the workflow while deleting cache keys.
           set +e
           echo "Deleting caches…"
           for cacheKey in $cacheKeysForPR
           do
-              gh cache delete $cacheKey
+              gh cache delete "$cacheKey"
           done
           echo "Done"
         env:
           GH_TOKEN: ${{ github.token }}
           GH_REPO: ${{ github.repository }}
           BRANCH: refs/pull/${{ github.event.pull_request.number }}/merge
+
+  cleanup-rust:
+    if: github.event_name != 'pull_request' && github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    concurrency:
+      group: cleanup-main-rust-caches
+      cancel-in-progress: false
+    permissions:
+      contents: read
+      actions: write
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+      - uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9
+        env:
+          DRY_RUN: ${{ github.event_name == 'workflow_dispatch' && inputs.dry-run }}
+        with:
+          script: |
+            const { cleanupRustCaches } = await import(`${process.env.GITHUB_WORKSPACE}/.github/scripts/cleanup-rust-caches.mjs`);
+            await cleanupRustCaches({ github, context, core }, { dryRun: process.env.DRY_RUN === 'true' });