I'm sure we've all bought a used bass that was gently cared for, but it still has annoying micro scuffing to the finish. The products I use to buff out a newly finished body will work equally well to clean up that used body. Since few of us have the tools a finishing shop would have, I'll write this from the perspective of working this without power tools
First off, you'll need several clean micro-fiber cloth. I buy these in a bulk pack at Costco, and cut them up into smaller pieces so I don't waste an entire cloth on one working session. I also like to remove the edge stitching so I don't accidentally impart scuffing that's worse than what I started to remove.
http://www.amazon.com/Unitex-Large-Ultr ... B00113SX5O
I use these cloths to apply 3M Perfect-it II onto the body in a small area. I then vigorously buff this area until the compound has been used up. A little experimenting will allow you to disciver how much pressure to apply to get the best results. It's critical you don't get a piece of debris under the cloth (you'll scratch the finish), so be careful around holes in the finish - pickguard mounting screw holes are the worst
http://www.autogeek.net/3mfiniimacpo.html
I use the same application process to then apply 3M's Perfect-it II to remove any remaining swirl marks
http://www.amazon.com/3M-Perfect-Foam-P ... B0009KMHS4
Finally, I'll use a silicone-free Carnuba wax to polish and protect the newly rejuvinated finish
Good luck with your clean-up efforts
all the best,
R