We've been experimenting. The powder that comes with it works good but is $$$. Tried CLR, questionable, sometimes good, sometime OK. Now trying Simple Green, but I've been laid off for two months, don't know how it's working.
I'm not sure, but doesn't CLR attack aluminum? I know it has a very high PH. Even some commercial degreasers, if left on too long, will turn aluminum black.