Mr. Good,
I use some laquer thinner applied with a tiny artist's brush. I use the same brushes to apply enamel Testor's model paint to front sights, especially the stainless steel front ramped sights on SS revolvers. These are really hard for me to see. I apply a coat of white and let it cure well, then the florescent green which seems to be easiest for me to see well. I also use this paint on blued guns. Eventually, especially with holster use, the paint needs refreshing. I normally clean off all the old paint and then apply fresh when I do this. The tiny natural bristle brush allows me to apply the laquer thinner in small amounts only to the paint without allowing much of it to run down onto the metal of the gun. I will apply the thinner, let it sit for a very few minutes, apply it again, by which time I can usually see some softening of the paint. I then wipe it thoroughly with a paper towel or napkin which will remove some of the paint. I reapply the thinner again a couple times, wipe again, more thinner, then more wiping. Each time I get off more paint. Usually after about three times doing this, about all the paint that remains will be in the serrations in the ramped part of the front sight. I tickle that with a bit more thinner and usually it will "wash" out of the serrations with only the movement of the brush. If you are concerned about using either, remove the grips and test a small area underneath them to satisfy yourself if damage will be done.
I don't allow the thinner to remain on the metal for any long period of time. The thinner also evaporates quickly after application. After the new paint is applied, or in your case if you intend to leave it completely clean, take a Q-tip with a small amount of your favorite gun oil and wipe down the sight and ramp and the barrel (if any thinner gets on it), then wipe off the excess oil with a rag, and you should be good to go. I have never noticed any damage to blued guns using this method, and no discoloration to the SS metal either. The laquer thinner works quickly and allows removal with just the paper towel or rough rag so there is no chance of scratching the metal with anything. I've not tried it, but fingernail polish remover might do the same thing, especially if it's fingernail polish on the sight. I'd just say to be careful not to get either the laquer thinner or the polish remover on the sight and barrel more than is absolutely necessary. The tiny paint brush allows you to do this well. Lay the gun on it's side with a rag underneath it so that if any of the thinner happens to run down or drip, it will mostly just fall off the gun to the rag.