What will my old mattress be recycled into?

Good question!
  1. If it was an innerspring mattress, the steel from the springs will be melted and remade into a number of different products. 
  2. The foam, either in the core or in the pillow top, will shredded down an used in carpet padding or bean bags.
  3. The wood from the box spring will be ground up into mulch.
  4. If there's fiber, it will be reprocessed and used for recycled fiber in filters and industrial equipment.