It's still trash. Before schools can get rid of old tables, chairs, computers and other surplus items, they must do all they can to sell the stuff. Then they can donate it or give it away as junk.
Most systems hold periodic auctions or take sealed bids on items that can turn a profit.
But for the most part, by the time a school system is ready to unload surplus, it's just junk. A school system can also donate surplus to a charity, to another school system or organization, or offer it as a trade-in on new merchandise. If the school still can't get rid of surplus, it is sent to the dump. Usually, low-end items like desks, chairs, tables and old computers end up as scrap and garbage. Buses, cars, and farm equipment usually bring in some money.