Years ago had client that wanted to know if there was a deduction for obsolete inventory discarded that could no longer be sold. I told him when he counts the ending inventory then the cost of goods sold will reflect this. This was one of the reasons that many businessmen, especially immigrants, opened up businesses with durable goods that did not spoil or become obsolete, I.E. an infinite shelf life. Clothing stores, shoe stores, hardware stores, jewelry stores, Etc. Even if the clothes, etc went out of style, you could just hold them for a generation or two and then they would come back in style.😉