Broken glass is an item which is the result of some glass being broken. Its main use is during the Sea Slug quest, where the player must use the glass on the damp sticks to get dry sticks, which have a "Rub-together" option to light a torch needed to continue with the quest.
It also plays a minor role in the Client of Kourend, In Aid of the Myreque, and Forgettable Tale... quests. In Client of Kourend, broken glass is obtained as a result of activating the mysterious orb near the Dark Altar. During Forgettable Tale..., the rowdy dwarf requests a random item in exchange for his Kelda seed, with broken glass being a possible item he requests. Broken glass is also one of the junk items found during In Aid of the Myreque when mining rubble piles. It can also be found cleaning uncleaned find at the Varrock museum.
There are six broken glass spawns in the Drunken Dwarf's house.
There is a broken glass spawn in one of the northern buildings inside of the Kourend Castle.