I don't know if it will work with a mat, but to get odors out of a freezer or such, you can fill it with charcoal or crumbled up newspapers. Maybe you could put the mat in a garbage back with crumbled newspapers or put a couple baggies (opened) of charcoal in a garbage bag, then lay the mat on top of the baggies before sealing the garbage bag. Leave either of these for a few days and see if the odor is absorbed.
Just a thought.
Carol B