Good one, Keb. Nerve is right. Once milk painted, it's PAINTED. That stuff is permanent! Did you apply any oil over the paint, or are you waiting for it to age gracefully?
If you are unfamiliar with powdered milk paint, it can be mixed with as much or little water as you choose. It can be thinned to where it's more of a wash--almost a stain. Some interesting things can happen with the yellow-orange-brown range rubbed back and oiled. I find painted guns intriguing, but it certainly DOES take some nerve.