diff --git a/background.js b/background.js
index 42aa2537..3887ea85 100644
--- a/background.js
+++ b/background.js
@@ -397,9 +397,8 @@ const SendLater = {
     // to display the old content for a message even though the server has the
     // new content; in this case it appears that even the server doesn't show
     // the new content, as evidenced by looking at the draft on mail.google.com.
-    // Compacting the Drafts folder after saving the message seems to solve
-    // this.
-    SendLater.addToDraftsToCompact(msg.folder, true);
+    // Cleaning the Drafts folder after saving the message seems to solve this.
+    SendLater.addToDraftsToClean(msg.folder, true);
 
     let targetFolder = await SLTools.getTargetSubfolder(preferences, msg);
     if (targetFolder) {
@@ -409,10 +408,10 @@ const SendLater = {
       // error.
       msg.id = null;
       msg.folder = targetFolder;
-      SendLater.addToDraftsToCompact(msg.folder, true);
+      SendLater.addToDraftsToClean(msg.folder, true);
     }
 
-    SendLater.compactDrafts();
+    SendLater.cleanDrafts();
 
     if (preferences.ignoredAccounts && preferences.ignoredAccounts.length) {
       let identity = await messenger.identities.get(composeDetails.identityId);
@@ -481,42 +480,39 @@ const SendLater = {
     return true;
   },
 
-  draftsToCompact: [],
+  draftsToClean: [],
 
-  addToDraftsToCompact(folder, force) {
+  addToDraftsToClean(folder, force) {
     if (
-      !SendLater.draftsToCompact.some(
+      !SendLater.draftsToClean.some(
         (f) => f.accountId == folder.accountId && f.path == folder.path,
       )
     ) {
-      SLStatic.debug("Adding folder to draftsToCompact:", folder);
-      SendLater.draftsToCompact.push(folder);
+      SLStatic.debug("Adding folder to draftsToClean:", folder);
+      SendLater.draftsToClean.push(folder);
     } else {
-      SLStatic.debug("Compact is already queued for:", folder);
+      SLStatic.debug("Clean is already queued for:", folder);
     }
-    if (force) SendLater.draftsToCompact.slforce = true;
+    if (force) SendLater.draftsToClean.slforce = true;
   },
 
-  async compactDrafts() {
-    if (!SendLater.draftsToCompact.length) return;
-    if (
-      SendLater.draftsToCompact.slforce ||
-      SendLater.prefCache.compactDrafts
-    ) {
-      await messenger.SL3U.waitUntilIdle(SendLater.draftsToCompact);
-      for (let folder of SendLater.draftsToCompact) {
-        SLStatic.debug("Compacting folder:", folder);
-        await messenger.SL3U.compactFolder(folder);
+  async cleanDrafts() {
+    if (!SendLater.draftsToClean.length) return;
+    if (SendLater.draftsToClean.slforce || SendLater.prefCache.compactDrafts) {
+      await messenger.SL3U.waitUntilIdle(SendLater.draftsToClean);
+      for (let folder of SendLater.draftsToClean) {
+        SLStatic.debug("Cleaning folder:", folder);
+        await messenger.SL3U.expungeOrCompactFolder(folder);
       }
-      SendLater.draftsToCompact.slforce = false;
+      SendLater.draftsToClean.slforce = false;
     } else {
-      SLStatic.debug("Not compacting folders, preference is disabled");
+      SLStatic.debug("Not cleaning folders, preference is disabled");
     }
-    SendLater.draftsToCompact.length = 0;
+    SendLater.draftsToClean.length = 0;
   },
 
   async deleteMessage(hdr) {
-    SendLater.addToDraftsToCompact(hdr.folder);
+    SendLater.addToDraftsToClean(hdr.folder);
     let account = await messenger.accounts.get(hdr.folder.accountId, false);
     let accountType = account.type;
     let succeeded;
@@ -2788,12 +2784,12 @@ async function mainLoop() {
   }
 
   try {
-    // We do this compact at both the beginning and end of the main loop
-    // because at the beginning there may be compacting needed as a result of
+    // We do this clean at both the beginning and end of the main loop
+    // because at the beginning there may be cleaning needed as a result of
     // messages that were edited or scheduled in the interim, and at the end
-    // there may be compacting needed as a result of messages sent and/or
+    // there may be cleaning needed as a result of messages sent and/or
     // rescheduled during the main loop.
-    await SendLater.compactDrafts();
+    await SendLater.cleanDrafts();
 
     let preferences = await SLTools.getPrefs();
     let interval = preferences.checkTimePref || 0;
@@ -2849,7 +2845,7 @@ async function mainLoop() {
           nActive,
         );
 
-        await SendLater.compactDrafts();
+        await SendLater.cleanDrafts();
         setDeferred("mainLoop", 60000 * interval, mainLoop);
         SLStatic.debug(
           `Next main loop iteration in ${60 * interval} seconds.`,
diff --git a/experiments/sl3u.js b/experiments/sl3u.js
index 0ae63eba..3159afbf 100644
--- a/experiments/sl3u.js
+++ b/experiments/sl3u.js
@@ -835,14 +835,21 @@ var SL3U = class extends ExtensionCommon.ExtensionAPI {
           if (waited) SendLaterFunctions.debug("Finished waiting until idle");
         },
 
-        // Compact a folder
-        async compactFolder({ accountId, path }) {
+        // Expunge or compact a folder
+        async expungeOrCompactFolder({ accountId, path }) {
           let uri = SendLaterFunctions.folderPathToURI(accountId, path);
           let folder = MailServices.folderLookup.getFolderForURL(uri);
           let msgWindow = Cc["@mozilla.org/messenger/msgwindow;1"]
             .createInstance()
             .QueryInterface(Ci.nsIMsgWindow);
-          folder.compact(null, msgWindow);
+          try {
+            folder
+              .QueryInterface(Ci.nsIMsgImapMailFolder)
+              .expunge(null, msgWindow);
+          } catch {
+            SendLaterFunctions.debug("expunge failed, calling compact");
+            folder.compact(null, msgWindow);
+          }
         },
 
         // Saves raw message content in specified folder.
diff --git a/experiments/sl3u.json b/experiments/sl3u.json
index 85546637..d49dec71 100644
--- a/experiments/sl3u.json
+++ b/experiments/sl3u.json
@@ -130,10 +130,10 @@
         ]
       },
       {
-        "name": "compactFolder",
+        "name": "expungeOrCompactFolder",
         "type": "function",
         "async": true,
-        "description": "Compact a folder",
+        "description": "Expunge (IMAP) or compact a folder",
         "parameters": [
           {
             "name": "folder",