In article ,
"Stormin Mormon" wrote:

The caution about aluminum or pot metal (typically zinc) is
good. I wonder if a VERY brief application might get the
crud but not damage the metal. Minute, or less. The time I
found oven cleaner useful was on Tecumseh carburetor. And
that was a very brief use.

Use a methylene-chloride based paint stripper instead. It will cut the
crud without dissolving aluminum.

Joe Gwinn