I've used Zep Fast505 Industrial Cleaner and Degreaser which is also at HomeDepot. It comes in spray bottle or 1 gallon sizes.
Same warnings about aluminum, I think, but it works great on the racks and V-trays and bowls.
I do wonder about the fish taste, though. I have 2 smokers and smoke fish in both almost daily for 6 months of the year. The only parts I clean (or I should say my wife cleans) are the removables. I never touch the interior. On occasion I smoke chickens and turkeys, like for Easter, and I have never had a fish taste in them. Strange!
Rich