Citristrip will eventually take that paint off if you want to try cleaning them up. Whatever the paint is, it’s hella tough and hard to take off.
I ended up using disposable metal paint trays, thick chem-resistant gloves (after melting some thinner ones), a stiff nylon brush, and a plastic putty knife as a scraper. Do it outside as well, or in a well-ventilated area otherwise.
Glop the stripper onto the mags in the trays, smearing it all over the painted surfaces. Wait a while. Not kidding, it may take a few hours to break down whatever that shit is. Try scraping with the putty knife or brushing with the nylon brush to see if anything starts coming off. Be careful with the putty knife as you can scratch the mags. The longer you let the the citristrip work, the less elbow-grease you’ll need to use. Slowly brush/scrape/glop and work the paint off. Some will come off in big strips, some in little flecks, others will seem horrifically slow. Stick with the method and you’ll get there.
I ended up with 8 sanitized plums when I did this back in 2010 Orr so. One was pretty scratched under the paint, another had a weird frosted appearance, and the other 6 were just normal looking plums. Considering the painted mags were a few dollars each and Russian mags were pretty hard to find at the time, it was worth the effort.