This rim was nasty but I cleaned it up to look pretty good. I do this for all of my barn find rims:
I use rust remover gel on the spokes and aluminum cleaner gel on the hub, applying with an acid brush. After a few rounds with those, I rinse and scrub with dish soap. Then clean it all with #0000 steel wool. The steel wool does a nice shine on the rim. Then with a small bottle of Krylon silver artists paint and a few sizes of artists brushes I do the spokes, 2 coats. It dries fast, I think its laquer. Has a matte look just like original plating and has lasted on all of the rims I have ever done. Then, with the same silver paint but I mix 50/50 with the same brand but gold, I do the nipples most of the time. Finally, I tape off the rim on both sides and clear coat it.