The oven cleaner sound like a great idea. I don't want to remove the fins unless absolutely necessary, they really are in nice original shape, and then you'd have to re glue them, and that brings up more questions about what glue to use...et cetera. Is there a particular brand of oven cleaner that is recommended? I would just try to keep the oven cleaner on the inside and not get it near the fins. I'll bet it harms aluminum. I'll give brake cleaner a shot too, but that stuff evaporates so fast I question its effectiveness.
