Both oven cleaner and drain declogger are lye. Caustic stuff, but predictable. It offgasses hydrogen, of all things, so don't do it in a little room with open flame or sparks. Hydrogen isn't poisonous or anything, and lye dissolves in water, so follow the safety instructions on the container and you'll be fine.

Anodization is a pretty excellent process, though, and you should probably consider having it re-annoed clear. Here's a guy explaining how to do it yourself, if you want to. Here's another description. Reading that, I sure want to.