You should be able to use a microwave to boil it pure as well. I believe this is the same as when you boil water and pour it between two cups repeatedly. You'll remove all the contamination allowing you to bring the water right up to 212 deg F. If you do this, and then drop a (not steril) spoon into the water, the water will "explode"... all the contamination on the spoon will transition from solid to gas immediately.