caustic soda

[Batfish]

Originally Posted by mmdooley

I tried oven cleaner and it did not work at all.

This is one instance where I found a name-brand to be important. Did you try "Easy-Off" oven cleaner?
I bought a generic brand figuring they were all the same and the generic did absolutely nothing to the anodizing. I then used Easy-Off and the anodizing was off within minutes.
For small parts, I put them in a small plastic dish, sprayed enough Easy-Off in the dish to cover them, then just swirled the stuff around in the dish until the anodizing was gone. I ran cool water through the dish until the chemicals were gone and had nicely 'de-purpled' aluminum shock caps :003:

Make sure you wear gloves and don't inhale the stuff.