It has a tenifer finish, which is supposed to be highly corrosion resistant. I pocket carry this pistol in a desantis pocket holster, and I wipe the slide down with Ballistol.
These spots showed up suddenly. Tried to scrub them off with corrosion x but they are there to stay.
Is this rust? I know that carry guns will look ugly eventually. Should I do anything to remove them?
Because of the "round" or circular shape of all of the marks, I don't think it's oxidation. Perhaps something that was atomized or sprayed near the gun landed on the slide and caused the damage?
Not rust. Did you use Bug Spray, Sun Block or something else while shooting? Looks to be over spray from an aerosol can or splatter from another chemical. If gun oil or a safe solvent for the Walther finish won't remove it - I'd try and live with it otherwise it might have to be refinished.
I once got a Carbon steel pocket knife all stained up by just cutting an apple. I eventually got it all off using Flitz but I am not recommending Flitz on your gun as I do not know how it would react with the finish.