My 22A-1 came back from S&W (second time in for the same problem, long story), and I took a look at the front sight. The factory finish on the gun (including the sight) appears to be some sort of applied coating, definitely not a blued process. I don't think it would be a good idea to use strong solvents to clean the surface (such as acetone, MEK, etc.), as they may damage the finish. I did notice that the finish on the front sight blade (especially the rear of the blade, where you would want to paint it) is extremely smooth, probably too smooth to allow paint to bond well to it. If you can't get the paint (or nail polish, Kickapoo Joy Juice or whatever) to bond to it, a bit of judicious sanding with 320 or 400 grit wet/dry sandpaper may be in order to give the surface enough bite to allow the paint to bond.