For any of the standard, non-o2 absorbing caps, you can either boil them in water for 15 minutes or soak them in the sanitizing solution of your chossing for the needed contact time.
Use Iodophor or Star San to sanitize oxygen-absorbing caps, since they, unlike One Step or oxygen cleaners/sanitizer, don’t need free oxygen to sanitize.
Sanitize only the amount of caps that you will use. Wetting them will render the caps useless in terms of absorbing oxygen for any batch after the current batch being bottled.