I agree...if you don't think you'll ever to get another take that good you could try to eq it out on a 30 band EQ or something. Ummm...cooledit pro has a pretty good hiss remover. Otherwise...why not redo them?
When you are just about to record something stack pillows and or blankets around your PC.
Just as soon as you are done with a take -TAKE THEM OFF!! You can damage the computer if it over heats. For short periods of time, though, you should be fine.