I have not tried using lye. When I first did some online research about removing aluminum a few years ago I found recommendations for both lye and CLR. I already had some CLR so I gave it a shot and it worked, so that's what I've been using. Also, the CLR appears to less hazardous, at least according to the MSDS. The black oxide may be problem on a crank shaft, but taps I use the CLR on (normally 3/8 & 1/2 NPT 8" lg. pulley taps) actually get aluminum stuck in the teeth less often after they have been in the CLR. Paul