I was degreasing my manual gear box with some oven cleaner without problems. Went to get some more (same brand, but 1st can was about 3 years old) and used it and the formula seamed to be different. It didn't foam like the 1st can did.

It turned the aluminum a little darker gray.

What is the best media to use on the casting?
Glass beads on light pressure?

Its still assembled and it doesn't need rebuilding.