Yes, rubbing alcohol is 100% safe to use with Fleshlights and other TPE sex toys.
Rubbing alcohol kills germs, bacteria, and viruses on contact－even COVID-19－which is why it's usually the active ingredient in hand sanitizer.
It used to be my go-to Fleshlight cleanser, since it was so cheap, effective, and easy to buy. However, since the coronavirus pandemic started, isopropyl alcohol has gotten way more expensive and harder to find on store shelves.