We've got a few machines we've inherited this way. For one client they needed confirmation that we had a sanitized infrastructure for our pentest and that we captured and logged all traffic to and fro. We billed them for the equipment and network link etc. Upon completion of the project we provided a certified copy of data destruction in accordance with their policies / guidelines and were left with a bunch of stuff. Scored two GPU cracking rigs, couple laptops, and some Cisco gear. I didn't complain. Granted now those rigs are a bit dated, but at the time 1080's were hard to get during the last mining rush so they definitely weren't cheap.