
	March 31, 2024		December 31, 2023
Manufacturing supplies	$	42.3	$	41.9
Raw materials	148.8		145.6
Work in process	502.4		496.1
Finished products	618.4		619.2
Subtotal	1,311.9		1,302.8
Allowance for obsolete and surplus inventory	(80.7)		(73.7)
Total inventories, net	$	1,231.2	$	1,229.1

Inventories are valued at net realizable value, with approximately 61% valued on the first-in, first-out ("FIFO") method and the remaining 39% valued on the last-in, first-out ("LIFO") method. The majority of the Company's U.S. inventories are valued on the LIFO method. The Company's non-U.S. inventories are valued on the FIFO method.

The LIFO reserve at March 31, 2024 and December 31, 2023 was $234.7 million and $232.1 million, respectively. An actual valuation of the inventory under the LIFO method can be made only at the end of each year based on the inventory levels and costs at that time. Accordingly, interim LIFO calculations are based on management’s estimates of expected year-end inventory levels and costs. Because these calculations are subject to many factors beyond management’s control, annual results may differ from interim results as they are subject to the final year-end LIFO inventory valuation.