I have decided to give up watching television.

Answer

It is not permissible to sell the television to even a non-Muslim, nor is it permissible to give it back to your relative. Anything haraam must be destroyed. When wine was declared haraam, the Sahaabah immediately dumped all their wine into the street drains. Those who had large stocks for selling destroyed it in the desert. The only option is to destroy the television set.