Recycling and organics carts can become contaminated by improperly sorted materials. Common contaminants include food, liquids, and food-soiled paper in recycling carts, and glass, metal, or plastic in organics carts.

Contamination has real consequences, degrading the value of recyclable materials collected, reducing the amount of beneficial compost that can be produced from the material collected in organics carts, and increasing the costs to process these materials.