I have cast aluminum parts as do most of you all on your cars. What is everyone using to clean them but not take the "old" off of them.
good old hot water from a steam cleaner , will not mess up aluminum . and on semis we had alot of polished stuff we didn't want to turn white . a little dawn and I mean little Dawn dish soap in the soap dispenser will take the oil film off without bleaching the aluminum . and when I mean a little like 1 table spoon per gallon of dilute otherwise you have a foam fight