How does one properly dispose of unwanted remote controls?

Most counties have "e-waste" drop off periods at certain times of year when you can drop off old computers, cell-phones, pc monitors, batteries, etc. Just throw your old remotes into the box with your other e-waste and leave it aside for your e-waste drop off day.

sometimes high schools will have a drop of site for electronics once a year just store it in a box until they have one.

Take them to a recycling centre, they should have a section for electrical and electronic equipment