Well, I dont do it at home, but know a lot of people that do, You can take them to the dump here, you first have to goto the town hall and get a permit, then to the dump they go, second, you could just take them to a garage (where they work on cars) at night, and leave them in their tire pile
, or, you could do what a lot of people here do, drive down a back road and dump them off in a ditch.