You made more money than just scrap because dude said "hey, that one works and is worth some coin." You want to encourage him to do it more in the future so you make more money off of his scrap in the future. Offer him something extra this time (he may not want it,) and tell him you will pay him for anything like this that he points out to you in the future ( a new deal.)



Or give him nothing extra, and start checking all his scrap for resellable stuff yourself. no fun.