Memory Leak in IE and FF

at my site ( http://gmaps.evilc.com ) I find it gobbles memory at an
alarming rate.
I have tried re-using markers, re-using overlays, all kinds of stuff
but no dice.

One thing I noticed was that if I minimise the window and then restore
it, it frees up loads of memory.
Is there a way I can force it to do this manually ?