I usually just buff really long and hard with a micro fiber wipe for light scratches/scuffs. Some recommend using tooth paste (NOT the GEL kind) and coating it, let it sit, clean/buff off. It takes longer but I prefer to just buff on a flat surface with my micro fiber.
There's always the option of going to a gaming store (usually Gamer's or small local shop) and letting them give it a whirl through their buffer. That costs a buck or 2 though normally. Generally this setup is just a drill press with a round buffer surface + buffing compound so you could DIY it easy if you have a drill press.
Disc repair kits generally operate on the same principle as the Game shop drill press only at a much slower speed. They do work but success can vary by kit due to build quality and what they use to buff. Do not use any kind of machine buff w/o some kind of lubricating buffing compound or you will regret it.