I am using odoo 13 ce, In my company, we are buying oil in Tins of 16 liters.  We are using this oil for the manufacturing process. After using the oil we send back this tin to our vendor and he refunds the price of this tin. Now I want to know that how could I manage Tin's inventory and how could I sell it because we are not buying it as a product. It is just the product container.