Freeing/deleting out of scope objects or data

How do you "free" an object or its assocated image? I have a bunch of objects (fxRenderObject) and large images for them. When an object comes into scope of the player, its image gets loaded up. How can I free it when it goes out of scope?

I think I have found where to identify the out of scope objects( SceneGraph::scopeCallback() ), but I would like to know how to unload them properly. Do you use SceneGraph::removeObjectFromScene() ?? I also noticed a post regarding scoping: www.garagegames.com/mg/forums/result.thread.php?qt=3249 that mentions timing this but I dont see where this is or if it relates to my problem directly.

Any tips would be greatly appreciated!

Thanks

CG