If they are not too badly scratched, I've had good luck w the disc-doctor manual machines. They use a very mild abrasive strip along w a liquid cleaner to polish the surface. Another very mild abrasive you could try is toothpaste. Some 'philes prefer Colgate, but ADA (American Digital Audiophile) as determined that "Crest effectively prevent dropouts, when applied as part of an audio hygiene program that includes regular professional care." ;~)
P.S. I am serious about the toothpaste part; it's a very mild abrasive.
P.S. I am serious about the toothpaste part; it's a very mild abrasive.