We use to use a standard 60 watt bulb and cook for as long as it took for the lens to clear. Be very careful when you touch the lens though as it does get very very hot. It may sound a little scary to some people but quite a few lens are treated this way before they are sold on the re-used/secondhand market. Although the store I was at sold equipment with up to a 6 month warrenty, we never had any returns so I'm guessing it is a virtually permanant fix. I've treated a lens I got for my Zenith cheap on a market the same way and at least 2 years later it still has no sign of the dreaded fungus returning.