Brass Punch works, but sometimes leaves a golden hue on the sight's finish. While most is removable, sometimes it is hard to get off. The Nylon Punch with Steel Insert does everything the Brass one will do WITHOUT marking up the sight or gun if you slip. There are all different sets and cheap enough for everyone to own one. The Nylon only set os about $6 bucks - scroll down list.

BROWNELLS NYLON/BRASS DRIFT PUNCH | Brownells