Adding destroy method, as suggested by @bartvde

lib/OpenLayers/TileManager.js

@@ -170,11 +170,25 @@ OpenLayers.TileManager = OpenLayers.Class({
         var layer = evt.layer;
         if (layer instanceof OpenLayers.Layer.Grid) {
             this.clearTileQueue({object: layer});
-            layer.events.un({
-                addtile: this.addTile,
-                retile: this.clearTileQueue,
-                scope: this
-            });
+            if (layer.events) {
+                layer.events.un({
+                    addtile: this.addTile,
+                    retile: this.clearTileQueue,
+                    scope: this
+                });
+            }
+            if (layer.grid) {
+                var i, j, tile;
+                for (i=layer.grid.length-1; i>=0; --i) {
+                    for (j=layer.grid[i].length-1; j>=0; --j) {
+                        tile = layer.grid[i][j];
+                        this.unloadTile({object: tile});
+                        if (tile.url) {
+                            this.manageTileCache({object: tile});
+                        }
+                    }
+                }
+            }
         }
     },
     
@@ -322,6 +336,31 @@ OpenLayers.TileManager = OpenLayers.Class({
                 this.tileQueue.splice(i, 1);
             }
         }
+    },
+    
+    destroy: function() {
+        window.clearTimeout(this.tileQueueId);
+        var map = this.map;
+        if (map.layers) {
+            for (var i=0, ii=map.layers.length; i<ii; ++i) {
+                this.removeLayer({layer: map.layers[i]});
+            }
+        }
+        if (map.events) {
+            map.events.un({
+                move: this.move,
+                zoomend: this.zoomEnd,
+                addlayer: this.addLayer,
+                removelayer: this.removeLayer,
+                scope: this
+            });
+        }
+        this.map = null;
+        this.tileQueue = null;
+        if (this.tileCache !== OpenLayers.TileManager.prototype.tileCache) {
+            this.tileCache = null;
+            this.tileCacheIndex = null;
+        }
     }
 
 });

tests/TileManager.html

@@ -19,6 +19,25 @@
         t.ok(tileManager.tileQueue.length, "Tiles queued from added layer");
         map.destroy();
         t.eq(tileManager.tileQueue.length, 0, "Tiles unqueued when map is destroyed");
+        tileManager.destroy();
+    }
+    
+    function test_destroy(t) {
+        t.plan(3);
+        
+        var map = new OpenLayers.Map('map');
+        var layer = new OpenLayers.Layer.WMS('WMS', '../img/blank.gif');
+        map.addLayer(layer);
+        map.setCenter([16, 48], 9);
+        var numTileListeners = (layer.grid[0][0].events.listeners.reload || []).length;
+        var numLayerListeners = (layer.events.listeners.retile || []).length;
+        var numMapListeners = (map.events.listeners.removelayer || []).length;
+        var tileManager = new OpenLayers.TileManager({map: map});
+        tileManager.destroy();
+        t.eq(layer.grid[0][0].events.listeners.reload.length, numTileListeners, "no listener on tile after destroy");
+        t.eq(layer.events.listeners.retile.length, numLayerListeners, "no listeners on layer after destroy");
+        t.eq(map.events.listeners.removelayer.length, numMapListeners, "no listeners on map after destroy");
+        map.destroy();
     }
 
     function test_manageTileCache(t) {