I got my satin wheel from the Rio Grande catalogue. The wheel is
a firm but not hard, about 3/4 inches wide and 3 inches in
diameter. It's wonderful for removing firescale or small specks
of solder. It'll also grind away prong tips or small findings in
a flash, so be careful near these areas.
Of course, the best thing to do is to try to avoid firescale
from the start. Don't skimp on flux, and then hit your work as
hot and fast as you can. I tend to use a huge flame, even for
small stuff. Then I get my hand in there to stick solder
People who watch me tend to shudder and walk away, but I don't
get much firescale that way!