If you aren’t sure whether or not an item is recyclable, it’s important to research the answer to this question instead of simply tossing the item in a recycling bin. If an item is not recyclable, tossing it in a recycling bin can contaminate the other recyclables. The entire contaminated bin of recyclables will then end up in a landfill all because of this minor mistake.

The only way to prevent this problem is to learn which items cannot be recycled. Here’s a look at some of the most common household items that end up contaminating recycling bins:

Disposable Coffee Cups

Many people toss disposable coffee cups into recycling bins everyday, but these items actually belong in the trash bin. Most recycling facilities cannot process the polyethylene lining on disposable coffee cups. For this reason, these cups are typically sent to landfills instead of recycling centers. However, it’s possible that the recycling center in your community will process the plastic lids used on disposable coffee cups even if they don’t process the actual cups.

Greasy Takeout Containers

Restaurants often put take out food inside clear plastic containers that are easy to transport and store. These containers are made out of a recyclable plastic, but that doesn’t mean it’s safe to put them in your recycling bin. If the plastic container still has residue from your take out food, it cannot be recycled at most facilities. Make sure your take out containers are not contaminating the rest of your recyclables by rinsing them out prior to tossing them in your recycling bin. The containers don’t need to be spotless in order to be processed, so there’s no need to spend a lot of time cleaning them. A quick rinse should remove the food scraps and residue that prevent these containers from being recycled.

Plastic Straws

It’s estimated that people in the U.S. use over 500 million plastic straws per day. Plastic straws are typically made out of polypropylene, which is a type of plastic that is also used to create yogurt tubs, plastic utensils, and toothbrushes. Even though this material is highly recyclable, the majority of recycling facilities will not accept plastic straws. This is mainly because of the size of plastic straws. The machines that recycling facilities use to sort and process recyclables are not designed to handle small-sized items. As a result, small-sized plastic items such as bottle caps and straws are sent to landfills.

Plastic Bags

Many people are surprised to learn that plastic shopping bags cannot be recycled, but it’s true. Although the bags are made out of plastic, they are difficult to process and often clog machines at recycling facilities. For this reason, most curbside programs do not accept plastic bags. There are special facilities that process plastic bags, but these facilities are not associated with curbside recycling programs. If you want to ensure your plastic bags are recycled, locate a special facility near you so you can schedule a drop off.

This is just a small sample of non-recyclable items that are often sent to recycling centers. Make sure you pay close attention to every item you put in your recycling bin so you don’t accidentally send something that could contaminate other recyclable materials.