Since yours are heat molded, I wouldn't recommend microwaving them (you can do this if you have no plastic bits in your liner... kills all the bacteria)
So, first thing I would do is soak them with as much anti bacterial febreze as possible. dry them at room temperature. If they still smell, do it again, throw in some gold bond. First step is to kill the bacteria.
Next step. Get rid of all of your synthetic ski socks and replace said stocks with Merino Wool. Get all merino wool socks.
Thing is, bacteria can't grow on merino wool. So if your feet get sweaty, the merino wont let the bacteria reach the inside of your boot. You can wear your socks 8 days in a row and they still wont stink unless you marinate them in something with a scent added (like perfume). So as long as you can get the bacteria currently in your boot to die, you can keep any from getting in there again by wearing merino wool.
I got new liners 2 seasons ago and have only used merino socks. My boots still smell fresh and clean. As do all of my shoes since I now only wear merino wool socks. They are magical.
I enjoy the Smartwool PhDs.
