BT BQ 98a(17) :מחייה בקורנסא וטרשיה‏ : he hit it [i.e. the coin] with a mallet and effaced it
See the entire entry for ṭrš#3 vb. to batter

BT BQ 98a(17) :מחייה בקורנסא‏ : he hit him with a mallet
See the entire entry for qurnās, qurnāsā n.m. hammer, mallet