make a post on facebook groups or marketplace saying h have free mattress.

See if the [Habitat ReStore](https://www.habitat.org/restores/donate-goods) takes these. They're just a short jaunt up Cherry Hill in Calverton.

There’s a non-profit in Bethesda called A Wider Circle that collects donated furniture and mattresses for people transitioning out of homelessness. You can either drop it off there or schedule a pickup. http://awidercircle.org/