Training to Strike the Silver

“Strike the Silver” means hitting someone’s jaw, usually a gangster or hoodlum who have silver grills in their mouth. So “training to strike the silver” refers to someone who is working out to get stronger in preparation for a fight.

Gym dude: What’re you working out for?
Other gym dude: I’m training to strike the silver, man.
Gym dude: Damn, alright, good luck!