Non-stock parts and how to account for them

If we are buying a part for one time on the shelf stocking or to be put on a vehicle at a later date but do not want to stock it with a part number, how are others handling these parts so they can get charged to a vehicle later? I didn’t know if there was a system way to handle these or if I will just need to number them. It would be great to have a little spot or inventory location where I could look up information on these non-stock parts other than having to formally set them up as a part. Anyone have any ideas?

We created an SOP for this. The SOP states that there will be noSpot-buy purchases. Items are required to be brought into inventory with an internal company number, bin, vendor, pricing, tags, etc. This makes life much easier. Now we can account for all inventory items. In the past we had a high % of non-file parts and some were being purchased frequently. If your parts room is high turning it could be difficult to charge out non-file parts on to a WO.