Definitely use J-bars or other things like C-bars or whatever. Don't throw out or sell your boots just yet. They've definitely packed out which is why they don't fit as well anymore but that is easily remedied with heel lift eliminators like J-bars. You put them around your ankle bone on the outside of the liner but inside the boot and tape it so that your achilles tendon has a more "restrictive" fit (in a good way). That makes it harder for your foot to move up which reduces heel lift.
A google search always helps. Just look up "Eliminate heel lift snowboard boots" or something of the like and you'll find a ton of solutions.
Last edited by TheNorminator; 05-02-2013 at 08:26 PM.