If a stock item is no longer needed, you can permanently remove it from the system.
This article will teach you...
How to delete Stock Items.
DELETING A STOCK ITEM IS A PERMANENT ACTION, IT CAN NOT BE UNDONE. THIS WILL HAVE AN IMPACT ON ANY MENU ITEMS THAT USE THIS STOCK ITEM AS AN INGREDIENT.
Go to Admin  > Stock Items  > select the Stock Item  > click Delete 
The Delete Stock Item Alert opens to confirm the Delete action. Please click OK  to proceed.
A second confirmation pop-up will open to confirm the delete action, click No  to complete the action.