Yikes! I will agree gloves are needed even for the Super Clean as it can seriously dry your skin, but the Zep may be too strong if it eats aluminum!
While I haven't any experience with early Monogram plastic, I have left Revell/AMT circa 1956 plastic in the super clean for days (weeks?) with no adverse affect.
I have also been told by Modelhaus that you can use Super Clean on their resin. It will turn the resin purple but has no other adverse affect.