Woodworkers ?

If you are just trying to mask the scratches, rather than remove them, a little English Leather in the right tone works quite well. It won't give the professional results that Tubegroover's method will, but you run little risk of hurting your speaker.

I'm serious about the English leather. I learned it from a Piano Mechanic. He used it to hide a small scratch on an almost unnocitable part of my piano. He noticed it--now I don't think anyone would notice it, even if you pointed it out to them.