The usual method of disposing of sand from all the digging was to scatter it discreetly on the surface. Small pouches made of towels or long underpants were attached inside the prisoners' trousers; as they walked around, the sand could be scattered. Sometimes, they would dump sand into the small gardens they were allowed to tend. As one prisoner turned the soil, another would release sand while they both appeared to be in conversation. The prisoners wore greatcoats to conceal the bulges from the sand, and were referred to as "penguins" because of their supposed resemblance. In sunny months, sand could be carried outside and scattered in blankets used for sun bathing; more than 200 were used to make an estimated 25,000 trips.