Check the edges of the box springs and mattress to ensure there are no wires poking through the surface. If you can see any of the edge wire or mattress springs you should reconsider your plan to donate your goods.
Many charities will not accept box springs or foundations with noticeable indentations or cracks, but they might take the mattress anyway.
Examine your mattress for noticeable stains. Some of them can be treated.
Use the shaker, sieve or sifter to spread baking soda in a layer all over the mattress. Place extra baking soda on the stained areas. Do not worry about using too much .It is fine to apply liberally.
Allow the mattress to sit with the baking soda on its surface for 24 hours. It will draw dirt out of the fabric and lift stains.
Vacuum the surface of the mattress until all the baking soda is gone.
Repeat the process on the back side of the mattress.
Surf the web for local halfway houses, women's and homeless shelters. Browse craigslist and check any online community bulletin boards for your area. Contact charities via e-mail or phone.
Consult your Yellow Pages for any other charities that would typically use beds as part of their daily operations and contact them by phone. Additionally, contact local places of worship to see if they have any members or parishioners who may have a need or if they could utilize your bedding in a mission project.
If unsuccessful in locating a charity in your area, consider advertising placing an online ad.
Arrange to deliver your mattress and box springs. Many charities will pick up the sets at your home.