I have expired stock. How do I add this as an expense as the stock is not able to be sold. None of the expense categories seem to fit this situation.

Hello Popsaw19-yahoo-c, 

Welcome to the Community page, 

So you cant put it into Quickbooks you will need to put it on the actual HMRC self-assessment form on their website. 

So you could put it against box 17 cost of goods bought for resale or goods used. 

If you are still unsure then reach out and speak to a trained accountant who would be able to advise you on how to record this in your self-assessment.