diff --git a/toolkit/components/social/FrameWorker.jsm b/toolkit/components/social/FrameWorker.jsm
index eeffc3dcc9b..e2fabf559b7 100644
--- a/toolkit/components/social/FrameWorker.jsm
+++ b/toolkit/components/social/FrameWorker.jsm
@@ -77,7 +77,7 @@ function FrameWorker(url, name) {
     if (!doc.defaultView || doc.defaultView != self.frame.contentWindow) {
       return;
     }
-    Services.obs.removeObserver(injectController, "document-element-inserted", false);
+    Services.obs.removeObserver(injectController, "document-element-inserted");
     try {
       self.createSandbox();
     } catch (e) {
@@ -103,8 +103,11 @@ FrameWorker.prototype = {
                      'location'];
     workerAPI.forEach(function(fn) {
       try {
-        // XXX Need to unwrap for this to work - find out why!
-        sandbox[fn] = XPCNativeWrapper.unwrap(workerWindow)[fn];
+        sandbox[fn] = workerWindow[fn];
+        // Bug 798660 - XHR has issues in a sandbox and need
+        // to be unwrapped to work
+        if (fn == "XMLHttpRequest")
+          sandbox[fn] = XPCNativeWrapper.unwrap(workerWindow)[fn];
       }
       catch(e) {
         Cu.reportError("FrameWorker: failed to import API "+fn+"\n"+e+"\n");
@@ -153,8 +156,14 @@ FrameWorker.prototype = {
       workerWindow.addEventListener(t, l, c)
     };
 
+    // This is necessary to keep the sandbox alive
     this.sandbox = sandbox;
 
+    Services.obs.addObserver(function cleanupSandbox () {
+      Services.obs.removeObserver(cleanupSandbox, "xpcom-shutdown");
+      Cu.nukeSandbox(sandbox);
+    }, "xpcom-shutdown", false);
+
     let worker = this;
 
     workerWindow.addEventListener("load", function loadListener() {
@@ -226,6 +235,8 @@ FrameWorker.prototype = {
       // now nuke the iframe itself and forget everything about this worker.
       this.frame.parentNode.removeChild(this.frame);
     }.bind(this), Ci.nsIThread.DISPATCH_NORMAL);
+
+    Cu.nukeSandbox(this.sandbox);
   }
 };