Plastic Caps Put in Garbage Cart/Bin However, you can recycle plastic caps if they’re screwed onto plastic bottles. Loose plastic caps should go in the garbage. They are too small for recycling equipment to separate out and recycle with other hard plastics. If a container has a cap that is made out of a different material, the cap should be removed and placed in the garbage. For example, a plastic cap from a paper juice carton should be placed in the garbage.