Considering you'd have to clean it before you paint it anyway, give it a wash and the best polishing you can and see how it looks. If it still looks lousy go ahead and paint it. I personally would not paint it but that's me. I've made some very dirty drums clean up beyond my expectations. If rust is just starting to appear you may be able to head it off at the pass. Just stay away from using steel wool or it will look horrible when you're done. A non-abrasive metal polish and rags from an old t-shirt should be all you need.

1. A nice 10 min soak in Dawn dish soap and water, scrub gently with a non abrasive scouring pad(the blue one, NOT the green one).

Dry well with soft cloth.

2. If rust spots are still there, scrub spots again with non abrasive pad and CLR(this stuff removes rust/lime as good as anything I've seen)

Rinse well and dry with soft cloth.

If rust spots are still there repeat #2

Finally polish with Novus(I've never tried this stuff but everyone here swears by it) or PEEK(this is the stuff I use. comes in mousse or paste. Also works fantastic) and a soft cloth

Your shell should now be beautiful.

Thanks guys. I soaked the shell and rims in dawn today. And will follow your advice for the rest of it. Once finished ill post a pic

As for painting it.

I wouldn't. Paint doesn't adhere to chrome very well. You will most likely end up with an even worse looking drum when the paint starts to chip off.

Consider having it powder coated or using one of the self adhesive "drum skins" type products.