Why can't I clean my PCV valve?

spray em out with brake clean
No, spray 'em out with carburetor cleaner. Most brake cleaner is no longer chlorinated, but chlorinated brake cleaner does still exist, and if it gets sucked into a running engine or otherwise burned it creates severely toxic nerve gas (phosgene) out the exhaust. You do not want to take even a tiny amount of that risk. Carburetor cleaner is the right stuff.