There is a thread about it with pics, but for some reason my search isn't working dammit.
Take 2 pots, one a bit bigger than the other. Fill the big pot about halfway and place empty smaller pot in so it floats on the water. Invert the big pot's lid and cover them both. Fill the inverted lid with ice (this will make the steam recondense). the water will evaporate up into the inverted lid and when it hits that cold surface, recondense and drip down into the empty smaller pot. the impurities are too heavy to get airborne and will be left at the bottom of the big pot. Voila!! distilled water. If it seems confusing, i assure you. Do it once and you'll feel like you are in a V8 commercial...
Good Luck...
out.