On Sep 7 2004, 12:40, Dan Williams wrote: glass tubes into a container don't I'm surprised nobody has thought of the obvious: mercury is considerably denser than glass, so the glass would float on the surface. All you have to do is skim it. Never mind skimmed milk, Sellam, you can have skimmed quicksilver ;-) A more interesting way would be to use some other metal to make an amalgam, leaving the glass behind, and then recover the mercury from the amalgam. Sodium's good. If you put sodium amalgam in water, it will decompose into nicely fizzy caustic soda solution and pure mercury, giving off hydrogen, which "burns rather readily". The usual method of filtering mercury is to use a small folded filter paper, with a very small hole torn in the point of the cone. The mercury will run through the small hole, but most of the rubbish, which floats on the top, will stay behind. You usually need to do this a couple of times. -- Pete Peter Turnbull Network Manager University of York