If players have completed The Hand in the Sand, Bert will ship 84 buckets of sand to the player's bank if talked to after the quest. This can be done once per day based on UTC time.
Buckets of sand and soda ash are used for making molten glass. Aside from Bert, players can collect sand from the sandpit near the POH portal in Yanille upon teleporting to their house. The sand can be banked at either Castle Wars or Edgeville depending on what teleportation jewellery the player uses. Otherwise, it'll be a long run to and from the Yanille bank.