Screw Caps Alternative ways to recycle Special Instructions Plastic screw caps should be placed back on the empty bottle/jar for recycling. Metal screw caps should be removed from glass bottles/jars and recycled loose. Place in a blue recycling bin for “Containers Only.” Loose plastic lids belong in the garbage. Plastic Caps Are Different Plastic caps have separate disposal instructions. Find out how to dispose of plastic caps. Recycle Metal Jar Lids Metal jar lids greater than 2-3 inches in diameter can be recycled. Make sure they are separated from their jars so they can be sorted correctly. Alternative Ways to Recycle Metal Screwcaps Are Scrap Metal Metal screw caps can be collected and recycled with other scrap metal. Simply separate aluminum caps (non-magnetic) from steel caps (magnetic).