I have used a polish called "Luster Pad" to shine my '98 CR frame as well as my 520's swingarm. The stuff works really fast and hardly any major elbow grease. Also "Mothers Chrome And Metal polish" works great too but a little more work involved(power buffer).I found the Luster Pad at my local bike shop. They also make a "Luster Lace" that is good for "lapping" round parts. Nzfred is right though, once you start polishing you can't stop or the oxidation sets in.
#4 0000 Steel wool and Semi-Chrome polish work well. I believe Aluminum oxide forms after reacting with water. It is not too hard to keep it looking good and bright, but I would not polish it to a high luster finish as that would drive you crazy trying to keep that look. I find old cotton shirts work best, but must be thrown away after a couple polishes as the rags become too black to use on anything else. That oxide forms in your chain adjuster bolt holes also, so remove them and put on anti-sieze compound so they don't freeze up.
Sorry if there is any misinformation here.. someone will straighten it out, I'm sure
Use a buffing wheel and rouge for a real shine. Take it off the bike to do it. Keep it lookin' good with 3M Aluminum Boat cleaner. This stuff is magic. Your better local hardware store or marine dealer will stock it. My bike has a polished swingarm, kickstarter, shifter, and kickstand. They all get scratched up eventually and need a re-buff, but the boat stuff does wonders once you have the surface polished up with the buffer.