Hi Mike, Seiger has the right idea, WD (water displacement 40) is a pretty good effort for anything you want to temporally clean... although, if I was really serious about cleaning a mag, original or not, I'd hit it with some break clean, and oil it afterwards.. I've probable cut apart 100 bottoms... and very few have been oil soaked to a point to where they were saturated... and those still had plenty of integrity left... They will stand a lot of cleaning... and to be truthful... oil just makes'em look better...
Best to you, til....lat'r...GT