diff --git a/src/as/com/threerings/util/ExpiringSet.as b/src/as/com/threerings/util/ExpiringSet.as
deleted file mode 100644
index 4e0e00095..000000000
--- a/src/as/com/threerings/util/ExpiringSet.as
+++ /dev/null
@@ -1,140 +0,0 @@
-//
-// $Id$
-
-package com.threerings.util {
-
-import flash.events.TimerEvent;    
-import flash.utils.Timer;
-
-/**
- * Data structure that keeps its elements for a short time, and then removes them automatically.
- */
-public class ExpiringSet
-{
-    /**
-     * Initializes the expiring set.
-     *
-     * @param ttl Time to live value for set elements, in seconds.
-     * @param expirationHandler Optional function to be called when elements are forcibly
-     *            expired, due to exceeding their TTL. The function should be of the form:
-     *              <pre>  function (element :*) :void { }  </pre>
-     *            and it will be called with the element expired from the set.
-     */
-    public function ExpiringSet (ttl :Number, expirationHandler :Function)
-    {
-        _callback = expirationHandler;
-        _ttl = int(ttl * 1000);
-
-        _timer.addEventListener(TimerEvent.TIMER, expireElements);
-    }
-
-    public function empty () :Boolean
-    {
-        return _q.length == 0;
-    }
-
-    /** Returns true if the set already contains this element. */
-    public function contains (element :*) :Boolean
-    {
-        for each (var e :ExpiringElement in _q) {
-            if (e.equals(element)) {
-                return true;
-            }
-        }
-        return false;
-    }
-    
-    /** If element is not present in the set, adds it and returns true; otherwise returns false. */
-    public function add (element :*) :Boolean
-    {
-        if (contains(element)) {
-            return false;
-        }
-        
-        // push the item on the end of the queue. since each element has the same TTL,
-        // elements end up being ordered by their expiration time.
-        _q.push(new ExpiringElement(element, _ttl));
-        _timer.start();
-        return true;
-    }
-
-    /** If element is present in the set, removes it and returns true; otherwise returns false. */
-    public function remove (element :*) :Boolean
-    {
-        var result :Boolean = false;
-        
-        // pull the item from anywhere in the queue
-        for (var ii :int = 0; ii < _q.length; ii++) {
-            var e :ExpiringElement = _q[ii] as ExpiringElement;
-            if (e.equals(element)) {
-                _q.splice(ii, 1);
-                result = true;
-                break;
-            }
-        }
-
-        if (empty()) {
-            _timer.stop(); // we ran out of elements. nothing left to expire.
-        }
-
-        return result;
-    }
-
-    /** Is the oldest element expired already? */
-    protected function headExpired () :Boolean
-    {
-        return empty() ? false : (_q[0] as ExpiringElement).expired();
-    }
-    
-    /** Called on a timer, expires any elements that exceeded their time to live. */ 
-    protected function expireElements (event :TimerEvent) :void
-    {
-        while (headExpired()) {
-            // pop the head of the queue and send it to the custom callback
-            var head :ExpiringElement = _q.shift() as ExpiringElement;
-            if (_callback != null) {
-                _callback(head.element);
-            }
-        }
-
-        if (empty()) {
-            _timer.stop(); // nothing left to expire. let's wait until something is added again.
-        }
-    }
-
-    /** Array of ExpiringElement instances, sorted by expiration time. */
-    protected var _q :Array = new Array();
-
-    protected var _timer :Timer = new Timer(1000); // check every second
-    protected var _callback :Function;
-    protected var _ttl :int;
-}
-}
-
-
-import flash.utils.getTimer; // function import
-
-import com.threerings.util.Util;
-
-internal class ExpiringElement
-{
-    public var expirationTime :int;
-    public var element :*;
-    
-    public function ExpiringElement (element :*, ttl :int)
-    {
-        this.element = element;
-        this.expirationTime = getTimer() + ttl;
-    }
-
-    public function expired () :Boolean
-    {
-        return expirationTime < getTimer();
-    }
-
-    public function equals (element :*) :Boolean
-    {
-        return Util.equals(element, this.element);
-    }
-}
-