diff --git a/keyserver/src/deleters/thread-deleters.js b/keyserver/src/deleters/thread-deleters.js
index d1e8db619..5d5a5f3a5 100644
--- a/keyserver/src/deleters/thread-deleters.js
+++ b/keyserver/src/deleters/thread-deleters.js
@@ -1,150 +1,169 @@
 // @flow
 
 import { permissionLookup } from 'lib/permissions/thread-permissions.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
 import {
   type ThreadDeletionRequest,
   type LeaveThreadResult,
 } from 'lib/types/thread-types.js';
 import { updateTypes } from 'lib/types/update-types-enum.js';
 import { ServerError } from 'lib/utils/errors.js';
 
 import { createUpdates } from '../creators/update-creator.js';
 import { dbQuery, SQL } from '../database/database.js';
 import {
   fetchServerThreadInfos,
   fetchContainedThreadIDs,
 } from '../fetchers/thread-fetchers.js';
 import { fetchThreadPermissionsBlob } from '../fetchers/thread-permission-fetchers.js';
 import { fetchUpdateInfoForThreadDeletion } from '../fetchers/update-fetchers.js';
 import { rescindPushNotifs } from '../push/rescind.js';
+import { removeBlobHolders } from '../services/blob.js';
 import type { Viewer } from '../session/viewer.js';
+import { blobHoldersFromUploadRows } from '../uploads/media-utils.js';
 
 type DeleteThreadOptions = Partial<{
   +ignorePermissions: boolean,
 }>;
 async function deleteThread(
   viewer: Viewer,
   threadDeletionRequest: ThreadDeletionRequest,
   options?: DeleteThreadOptions,
 ): Promise<LeaveThreadResult> {
   if (!viewer.loggedIn) {
     throw new ServerError('not_logged_in');
   }
   const ignorePermissions =
     (options?.ignorePermissions && viewer.isScriptViewer) ?? false;
 
   const { threadID } = threadDeletionRequest;
 
   const permissionsBlob = await fetchThreadPermissionsBlob(viewer, threadID);
 
   if (!permissionsBlob && !ignorePermissions) {
     // This should only occur if the first request goes through but the client
     // never receives the response
     const { updateInfos } = await fetchUpdateInfoForThreadDeletion(
       viewer,
       threadID,
     );
     return { updatesResult: { newUpdates: updateInfos } };
   }
 
   const hasPermission = permissionLookup(
     permissionsBlob,
     threadPermissions.DELETE_THREAD,
   );
   if (!hasPermission && !ignorePermissions) {
     throw new ServerError('invalid_credentials');
   }
 
   // TODO: handle descendant thread permission update correctly.
   //       thread-permission-updaters should be used for descendant threads.
   const threadIDs = await fetchContainedThreadIDs(threadID);
 
+  await fetchAndDeleteThreadBlobHolders(threadIDs);
+
   const [{ threadInfos: serverThreadInfos }] = await Promise.all([
     fetchServerThreadInfos({ threadIDs: new Set(threadIDs) }),
     rescindPushNotifs(
       SQL`n.thread IN (${threadIDs})`,
       SQL`IF(m.thread IN (${threadIDs}), NULL, m.thread)`,
     ),
   ]);
 
   const time = Date.now();
   const updateDatas = [];
   for (const containedThreadID of threadIDs) {
     for (const memberInfo of serverThreadInfos[containedThreadID].members) {
       updateDatas.push({
         type: updateTypes.DELETE_THREAD,
         userID: memberInfo.id,
         time,
         threadID: containedThreadID,
       });
     }
   }
 
   const [{ viewerUpdates }] = await Promise.all([
     createUpdates(updateDatas, { viewer, updatesForCurrentSession: 'return' }),
     deleteThreadsFromDB(threadIDs),
   ]);
 
   return { updatesResult: { newUpdates: viewerUpdates } };
 }
 
+async function fetchAndDeleteThreadBlobHolders(
+  threadIDs: $ReadOnlyArray<string>,
+): Promise<void> {
+  const query = SQL`
+    SELECT extra
+    FROM uploads
+    WHERE container IN (${threadIDs})
+  `;
+  const [rows] = await dbQuery(query);
+  const blobHolders = blobHoldersFromUploadRows(rows);
+  await removeBlobHolders(blobHolders);
+}
+
 function deleteThreadsFromDB(
   threadIDs: $ReadOnlyArray<string>,
 ): Promise<mixed> {
   const deletionQuery = SQL`
     START TRANSACTION;
     DELETE FROM threads WHERE id IN (${threadIDs});
     DELETE FROM communities WHERE id IN (${threadIDs});
     DELETE FROM ids WHERE id IN (${threadIDs});
     DELETE d, id, e, ie, r, ir
       FROM days d
       LEFT JOIN ids id ON id.id = d.id
       LEFT JOIN entries e ON e.day = d.id
       LEFT JOIN ids ie ON ie.id = e.id
       LEFT JOIN revisions r ON r.entry = e.id
       LEFT JOIN ids ir ON ir.id = r.id
       WHERE d.thread IN (${threadIDs});
     DELETE FROM memberships WHERE thread IN (${threadIDs});
     DELETE r, i
       FROM roles r
       LEFT JOIN ids i ON i.id = r.id
       WHERE r.thread IN (${threadIDs});
     DELETE m, im, u, iu
       FROM messages m
       LEFT JOIN ids im ON im.id = m.id
       LEFT JOIN uploads u ON u.container = m.id
       LEFT JOIN ids iu ON iu.id = u.id
       WHERE m.thread IN (${threadIDs});
     DELETE FROM uploads WHERE container IN (${threadIDs});
     DELETE FROM focused WHERE thread IN (${threadIDs});
     DELETE n, i
       FROM notifications n
       LEFT JOIN ids i ON i.id = n.id
       WHERE n.thread IN (${threadIDs});
     COMMIT;
   `;
   return dbQuery(deletionQuery, { multipleStatements: true });
 }
 
 async function deleteInaccessibleThreads(): Promise<void> {
   // A thread is considered "inaccessible" if it has no membership rows. Note
   // that membership rows exist whenever a user can see a thread, even if they
   // are not technically a member (in which case role=0). For now, we're also
   // excluding threads with children, since to properly delete those we would
   // need to update their parent_thread_id, and possibly change their type.
   const [fetchResult] = await dbQuery(SQL`
     SELECT t.id
     FROM threads t
     LEFT JOIN memberships m ON m.thread = t.id AND m.role > -1
     LEFT JOIN threads c ON c.parent_thread_id = t.id
     WHERE m.thread IS NULL AND c.id IS NULL
   `);
   const threadIDs = new Set(fetchResult.map(({ id }) => id));
   if (threadIDs.size === 0) {
     return;
   }
-  await deleteThreadsFromDB([...threadIDs]);
+  const containerIDs = [...threadIDs];
+  await fetchAndDeleteThreadBlobHolders(containerIDs);
+  await deleteThreadsFromDB(containerIDs);
 }
 
 export { deleteThread, deleteInaccessibleThreads };