You mostly dismantle them, then buy for 10 shards gift token from zavala, at the end of strike you get bonus 6-7 rep tokens, its +- 1 strike 1 engram from vanguard just for tokens
similar yes. buy the medalions from Tess at the tower, and activate them from your inventory before doing an activity. each medalion costs 50 bright dust and last for 4 hours.