1. Create a SCRAP location called "Consumed in Maintenance"

2. Scrap each Product you "use"

3. (for extra credit) Add a button to the Maintenance Request to help the user SCRAP, auto populating the correct location for them:

Something like this would do the trick (if you are worried about hardcoding action and location id's  -  check out the EVAL attribute for XML files):

<button string="CONSUME PRODUCT" 
        name="594" 
        type="action"  
        context="{'default_scrap_location_id': 168,}"/>

I have the same concern. Was there any solutions ?