There is a state fee that’s charged for each gallon of paint purchased in Colorado that allows you to take unused paint to any paint store for recycling. A pro tip here is to always keep at least one gallon (in the original container, and in a conditioned space) of each paint used in your home, clearly marked with where each one was used. When you choose to do a small project or touch-ups you will have what you need. Also, if you put your home on the market, the new owners will always want to have the old paint on hand for identification purposes.