A friend dragged a Winchester 52C target rifle out which has been sitting in a case for 25 years, and I've offered to try to clean it up for her. Needless to say, it's rusty - especially on the Redfield Olympic sight. Any suggestions for removing the black rust stains which are remaining on the scale part of the sights after I have worked on it with Hoppe's?

I've had good luck using Flitz's Metal Polish for removing rust in these types of situations. The good thing about Flitz's is that it won't remove the blueing as well. I just put some on cotton balls and rub until the rust is gone. Anyway that's how I do it but I'm sure you'll get other suggestions here.
Jim

0000 steel wool and WD
bill

JMO, but the 'black rust stains' are blueing. If you're trying to remove that from what should be a bare silver finish on a sight scale, I'd either use an appropriate grade of wet or dry paper to match the original polishing or a rust/blueing remover. Of course, polish in the same direction as the original polishing marks.