Buy OSRS Soft clay
Soft clay is a key material in Old School RuneScape. Players use it to train the Crafting skill and the Construction skill. It is also needed to make magic tablets in a player-owned house, such as teleport tablets.
You can shape soft clay on a potter's wheel to make items like pots, bowls, pie dishes, plant pots, pot lids, and cups. In Construction, it is used for things like shelves, firepits, and a pond. Soft clay is tradeable and noteable, but it does not stack in your inventory.
Soft clay is also needed in many quests. These include Prince Ali Rescue, Dragon Slayer I, One Small Favour, The Golem, Enakhra's Lament, In Aid of the Myreque, Getting Ahead, and Swan Song. It is used in a Varrock Easy Achievement Diary task too.
Making soft clay yourself takes time. You must add water to clay one piece at a time, use the Humidify spell at Magic level 68, or mine clay while wearing a bracelet of clay. Buying soft clay skips all that work, so you can start crafting and building right away.