I'm a huge fan of Evaporust & Oxalic Acid... but let me save you some time/$$$/heartache... I'm sorry, but IMHO your rusty wheel is too far gone for any chemical magic to repair. They work best when rust is just starting to bloom thru pinholes over good chrome (the rust looks "orange")... but once rust has progressed too far the chrome has been consumed (it looks brown). Even if you remove the brown rust you'll be left with only bare dull steel, it won't be shiny chrome anymore.
Only way to fix that is to strip down & rechrome... which ain't cheap nor easy to get done in envirogreenie countries anymore.
Second best is to find an identical part in better condition... preferably of same age if these things have datestamps... afaik these things were made in huge numbers BiTD, that wheel rim is likely shared with many other bike models.
I'm not a close follower of market prices for Schwinns (I'm more into British)... but I dare say their numerous retro repops they've endlessly churned out in recent years can't be helping resale value of used/crusty examples of the originals.
Pushbike restoration economics isn't too unlike classic car projects... if you're thinking of fixing up just to sell, you're usually better off just selling as-is... except in very rare examples - you're unlikely to recoup fixingup costs in your eventual sale price.
Don't know what Schwinn Stingrays sell for, vaguely remember seeing some asking $300-500 in freshly restored or mint survivor condition...? Might be wrong. The Brit arrow frames I lust after of similar era seem to be selling around the $1k mark... but to do a proper paintjob & rechrome would probably cost about that. Plus about same again to replace any rare minor bits that usually get broken or wornout.
Or for a totally whacked out scenario... go check out auction results of Merc 300SL gullwings... at one such sale in recent years, an unrestored unmolested Barn Find car was bought for nearly twice what a fully restored one was sold for. And the latter barely fetched enough to pay for a proper professional restoration job, assuming the old car came to you free.
Heck, we call it a "hobby" because it sure ain't no "good investment"
