How do you test old style pcv ?

Basically a PCV valve is a controlled vacuum leak to suck vapors from the crankcase the check valve and the spring are there to prevent backfires from entering the crankcase. So generally speaking soaking the valve in solvent to clean it should suffice. As long as the valve isn't plugged with gunk and the spring works the valve is good. You changed them in the old days because it wasn't worth your time to clean them.