Using stock for own use in the business? How to deal with it?

Hi,

I would like someone to tell me how to deal with an issue as follows:

My company sells flooring tools to the trade so we keep a stock of them for re-sale.  However we also use the same tools we sell for our own fitters so staff dip into the stock and take tools for use. This is legitimate but how do I actually account for this?

Someone suggested self invoicing but that does not sound right to me.  What is the best way to deal with this situation?

Any help would be appreciated.

Best wishes,
Stefan