Old prescription medicines should never be flushed down the toilet, since the residual effects of the medicines can contaminate both public and natural waterways. Instead, there are proper disposal containers at many national drug store chains. But did you know you shouldn't flush over-the-counter meds either? Mix them with something unappetizing like old coffee grinds and place them in an airtight container and toss it in the trash. Don’t follow the old-fashioned tip of mixing pills with peanut butter; wild animals find peanut butter tasty and could overdose if they get into your trash.