Where do large companies “write off” iron?

Question

Iron

Such a question:
Everyone is well aware that in high-tech companies there are quite large requirements for the reliability of iron and its performance. Starting from servers and communications, ending with phones and old computers.
So here's the question. And what do companies do with old hardware and can you buy it somewhere at an adequate price?

Answer 1

the contour (and other companies) periodically distributes "old" servers
not so long ago saw off the "retirement" of the monster, which cost 15 million - on Habré the article was

Answer 2

there is a bunch of such iron on all sorts of flea markets on the Internet, but what for it is necessary, iron in such companies has been working for 5 years or more, so there is not much point in buying even for cheap.