I'm building an application that creates a lot of object instances and
moves them around among a number of collections. I've tried to
deallocate objects when I'm through with them, but I'm not getting
them all. After a while I have a huge buildup of dead objects.

I've run dozens of tests trying to duplicate the problem, but Excel
cleans up after me even when I'm deliberately being a slob. (It
destroys the objects when control leaves the object's scope or on
program termination--just like I'd expect.)

Any way to determine what might be pointing at obsolete objects? Any
common memory management pitfalls?