eBay all the way. If you're able to sell them, it's important to validate that they're fully tested - or else it's best to sell them as is for parts/repair to be safe with customer expectations (at a discount with no returns). Simply look up the model numbers on eBay and then filter by recently sold/completed items to see what they're moving for. If there are a lot, you'll have to decide whether you want to list them individually (make more $), or as lots (faster to move for less). Check to see if you can track down any software or install disks for them too to complete the sets.