A tin filled with gypsum is used in Recruitment Drive during the Miss Cheevers challenge. It is one of the 9 stages of tins used during the quest. The gypsum filled tin is created by using gypsum on the empty tin. It should then be filled with a vial of liquid to create the tin (hardening). The tins are then used to create a plaster cast for the bronze key needed to complete the challenge. Using the wrong ingredients can result in a useless tin (strange).