use 000 steel wool and chrome polish (I use mothers). Works for getting those little rust spots out. Scratches are pretty hard to cover up since they are in the coating but a good quality polish will work wonders.
After you are done polishing, apply severl coats of carnuba wax. May dull the chrome a little but it does wonders for the cheap japanese chrome to keep it from re-pitting.
0, 00, and 000 steel wool can be had at home depot. I work on so much rusty junk I buy them in the 9 pack. Put a little dab of chrome polish on the surface and then work it in with the steel wool. Working with the bare wool will clean the rust really quickly but can sometimes leave very tiny scratches if the chrome is soft (as the cheaper chromes tend to be). Just work it in with some elbow grease and you should be good to go.
To clean off the minor rust spots, I use my 8" buffing wheel (mounted on a bench grinder) with very fine buffing polish. Not only does it take away the rust, the chrome is left without any scratch marks and the rust spots are removed. I have some before and after shots in my camera from my current build - I'll have to post these later - for now I have to get back to work...