Just quit. Just put down a half empty pack and decide you don't want them anymore. Keep the pack around, and test the strength of your resolve. How strong are you? Really?
Pick three days straight where you can be alone, sleep a shit load, and warn everyone to stay away. Thats how I did it. 9 years, 3 packs a day. Done. It was hard, but its doable. I also, after the three days were up, ate the shit out of apple jolley ranchers. Always carried a bulging pocket full of 'em. But during the three days, I slept, got up ate something, pee'd, went back to bed.. Bit the head off of anyone or anything that dared move in my presence.
Keeping the half empty pack is a psychological thing. Its not that you tossed them, don't have them, and can't have them.. You have them and don't want them. It makes a world of difference. I kept my pack in the junk drawer for a couple of years afterward.