Pretty easy 3 step process.
#1 Clean your mags backs with 91% Isopropyl Rubbing Alcohol.
#1a Be sure to let them air dry of the Alcohol for a few minutes.
#2 Using fingernail polish, color of your choice is fine, paint the #'s, Logo, and Caliber ID. Of course you're going to be painting all over the markings. Go ahead and do it. Unless you want the dots painted too, avoid getting polish in the circles.
#2a Let the fingernail polish dry. Usually doesn't take long. I let mine dry for about 20 minutes.
#3 Using NON ACETONE, I repeat, NON ACETONE Fingernail Polish remover, to your cleaning pads, the same ones you use to clean your bore and such with, just lightly start rubbing the mag. You'll see the excess overage start to clean off leaving the markings filled in. You might want to use a 2nd clean pad to get a good cleaning of the excess polish. AGAIN !!! NON ACETONE Fingernail Polish !!!
After letting them dry. You can do it right away, or even wait another day, do a 2nd coat and repeat the procedure if you wish. I did and the 2nd coat did make a difference and filled in the markings even better.