Sounds like you have nickel plated tuners that have oxidized. A mildly abrasive polishing compound and some elbow grease should work. Keep the compound wet.
A lot of the Fender tuners were nickel plated, not chrome. Nickel is not a bright finish like chrome. I've never seen brushed tuners on Fenders unless they were cleaned with steel wool or sandpaper.
Steel wool will scratch nickel plating.
mech