Some may wonder why it is okay to put plastic containers (like a yogurt cup or water bottle) in the recycling bin, but not plastic bags. Simply put, not all plastics are created equal. Plastic bags are made with a different resin than other plastics allowed in single-stream recycling bins.
The types of plastic used for plastic carrier bags has a different purpose than the plastic used to make a water bottle. Plastic bags get dirty in the single-stream process and get stuck in machines that sort recyclables, and mess up the process. Facilities that recycle plastic bags require them to be clean, so by recycling them separately, this is easier to achieve.
You can take clean, carrier bags and newspaper bags back to chain grocery stores most of the time. Often, they have designated areas where you can easily drop the bags off. So, always remember to bring any carrier bags that are clean and dry back to the store you got them at so they can go on to be properly recycled.