I have had luck using 1/2" of vinegar in a 3"x8" ish tupperware, microwave for 30 seconds then soak for 30-60 seconds per side. Repeat until you have the desired colour.

Its real important that you clean with acetone, and wear rubber gloves. Also wear glasses and maybe a respirator, microwaved vinegar has a violent ammonia stink.

I saw in Charlie's video he uses steel wool between dips, I never tried it but im sure it would help even out the finish.

Here is his video http://www.youtube.com/watch?v=DRtEPDzCa2A