Hi
The materials which will be consumed in the production of any semi-finished goods or finished goods are generally called operating supplies. These materials can only be procured and cannot be sold to customers, hence these materials' master data do not have sales data.
Examples:
Valuation class 1210 can used for materials that will be asset to the company and will be used in manufacturing activity but over the period of time it will depreciate. Any machine tools; fork lifts etc can belong to this class.
Valuation class 3030 can be used for materials like engine oil that will be consumed in maintenance activity of the machine/ plant
similarly Valuation class 3031 can be used for materials to be consumed in the process of production.
Regards
Saket