Hi Dave, Congrats on the acquisition. It appears to be a 6 Lug Drum, correct?
As Tommy states, and he's probably no doubt correct, that the yellowing originates from the underside of the wrap, therefore might not likely be able to be removed?
Since neither of us can see the drum in person, it's a bit hard to determine this.
What I've used, and recommend for polishing a shell that is gentle, and "might" (Notice I say might) alleviate-lessen the yellowing, and will bring up the gloss, will be a good hand glaze, such as a product from 3M (Their Imperial, or Perfect-It Line)
A cheaper, and more easily gotten glaze-polish would be the Pint Bottles of Meguiars Deep Crystal System, but I personally like the 3M stuff better.
Waxes offer some help, as most commercially sold waxes are combinations of a cleaner, a polish, and a sealer all in one. They contain detergents also, and do help clean crud, grease, smoke film, and other nasties stuck to the shell. A small soft detailing brush, or a small soft paintbrush will help remove any dried wax around lugs, badges, and strainers etc.
Remember not to try really hard rubbing, and trying to get immediate results. Usually, 2, or 3 light to medium applications of a glaze work better than trying just one application, and trying to rub like crazy with excessive pressure.
Hope this helps, Mark