Are they paid to actually destroy them? Or just to dispose of them how they see fit? A massive amount of those get bought by the pallet, and after they have their drives wiped/replaced get sold on Ebay.
This can range from just crushing drives all the way to running a hydraulic punch through any non-volatile storage on circuit boards (including flash used for UEFI). This is common enough that most manufacturers will provide a guide to all the non-volatile storage in a product: Statement or Letter of Volatility.
I've gotten some great deals on high-end networking equipment (e.g. Juniper, Arista) by buying boxes that had the SSDs removed & crushed. It's a little annoying to track down replacements, but doable.