To dispose of unused expired medication you can mix the expired medication with an unpalatable substance such as dirt, cat litter, or used coffee grounds.
Then either bury the old expired medication into the ground where an animal or something cannot get to the medication.
Or you can place the expired medication in a sealed plastic bag and then throw it in the trash after the dirt, cat litter or other stuff is mixed in with the medication.
Also a lot of Pharmacies have ways of disposing of expired medications free of charge to safely expose of the medications.
So you can check with the Pharmacy to see if they will take back expired medication which most will including CVS.