Quickly cleans carbon build-up on your soldering iron tip. Block weighs 100 grams. Keeps tips bright & wet. Non-abrasive so will not damage when cleaning & re-tinning tips makes old soldering iron tips like new. Sal Ammoniac, also called a tinning block, quickly cleans any carbon build-up that collects on the tip of a soldering iron. Simply rub the tip of a hot iron against the block and in seconds, the tip is clean, bright and hot. This block lasts a long time. For best results a longer lasting soldering iron tips, use the tinning block occasionally to re-tin the surface of your tip.