| DISCLAIMER: This is what worked for me. It may not work for you. Use at our own risk.
I have tried the auto polish route and had mixed results.
Polish is really liquid sandpaper. There are many levels of abrasiveness available. Meguiars is the most commonly available. Start with a light polish and get heavier only if you need. Expect to pay roughly $10 per bottle.
I usually wear a long-sleeved dress shirt when I play, and the cuff buttons leave really fine marks. On one guitar, polish took out the very finest scratches, but left some of the heavier, which were not very heavy. On another, it did nothing. On a third, it left a haze in the finish.
If you want to try it, use a very clean microfiber cloth on an inconspicuous spot with little pressure; let the polish do the work. Microfiber will not scratch on its own, but will grab on to a lot of other matter if it can; if you drop it on the floor, don't use it again until it is washed or else you will be rubbing whatever was on the floor into your finish, making new scratches. Small areas, slow speed, gentle touch. The only way to get rid of significant marks completely is to strip the finish and reapply.
If water does not remove gunk from the plated metal, lighter fluid is usually safe. If you have lemon oil to use on the neck, that may also work on the metal parts. On a guitar with raw bridge saddles, I was getting discoloration from my hand oils. After polishing with metal polish, I applied a light layer of clear fingernail polish. It is not noticeable, and the discoloration has not returned.
As to the fretboard, it may have lost its color as it dried out. When the bass is unstrung, use metal polish (Flitz, Simichrome) on a cloth to clean and polish the frets one at a time. After that, apply lemon oil to a cloth and clean the wood. Don't over do it with the oil - once a year is probably sufficient. Rub down the fretboard with a soft cloth after it has been cleaned and lightly oiled.
Good luck!
__________________ “...and those who have not swords can still die upon them." - J.R.R. Tolkein | Christian Praise & Worship Bassist Club Member #386 | Team Trace Elliot #92 |