Mary,,those brass bleed off screws on propane tanks,,Dang workers that refill the tanks alway manage over time to round out the screw head slots ,,,ive always had to throw out a hint,,Hey careful now don’t round off that screw head Slot,,35-40 bucks for a new valve,, Why they can’t just change out the air bleed screw I asked ,,we don’t do that Here,,💕🙏🇺🇸