They sell it. About a year ago fb decommissioned an old server design, leading to a huge glut of used Xeon E5-2670s flooding the market. Gamers snapped them up for next to nothing.

https://www.reddit.com/r/pcmasterrace/comments/3smipw/psa_th...

No, they sell it. This seems to be the main reason why E5 Xeons became really cheap some time ago.

http://www.techspot.com/review/1155-affordable-dual-xeon-pc/