Buy a tap and clean the threads up so the new ARP studs go in just using your fingers. Like Sticks said you only put them in once when you re-torque you will have to make sure the stud has not bottomed out again. I backed mine out about 1/4 of a turn. The tap, brake fluid and vacuum will get them pretty clean. I was surprised on how rusted and dirty the stock ones were. My head gasket is still holding and I have hit 50 plus a couple of times. I try not to go that high but with the twins and 150 injectors it gets that high pretty fast if I am not careful.