I clean my car religiously and it wasn't there yesterday!
I've tried normal car wash soap, dishwashing soap (I know..it's bad), rim/tire cleaner, bug/tar remover, paint cleaner, googone, and nothing will removed it!
I had something similar happen to me once in my old Jeep when I cleaned the rims with simple green rim cleaner. It left a residue that never went away for as long as I had it. Dunno what that was.
Sorry . . . this is no laughing matter . . . this is very serious . . . this is me being serious . . . what kind of cleaner did you use last time ?? on your wheels/tires/car . . . it almost looks to me like soap residue . . . but with all the methods you say you have used, it hasn't come off . . . which tells me something has most likely stained your clearcoat. could it have been bird ***** ?? the acid in animal feces has been known to do some bad things to clearcoat but I wouldn't think it would overnight. What type of rag are you using?? ever try one of those bug n' tar remover sponges ?? it's like a spongs with a fishnet around it and it does an amazing job . . . that, in combination with bug n' tar remover may just do the trick. Good Luck . . . sorry about the semen comment . . . but ya have to admit . . . it does.
You're screwed! Seriously though, is it only on that one rim or is it on the other one on same side? My guess is you got in something on the road...Lord know's what! Don't know what else to suggest but hopefully it not the clearcoat stained. Good luck with it!
I've long since given up trying to keep my wheels clean. They're going to get dirty and crapped up no matter what with the amount I drive my car. It's not that noticeable on your wheel.
Take some clearcoat safe polishing compound with a soft cotton cloth and see if that removes the marks. That has worked for me in th epast for these kind of things. Kit and Meguires make good ones that don't scratch and you can get them at Wally World or Advance Auto Parts.