I won't dispute the premise that heat will kill the mold, but the heat will also dry out the glue that holds the liner in place. Not only that, but it will further dry the wood that the case is made of and make it even more brittle than it already is. Liners frequently roll up and peel away anyway. The box wood is very thin and could easily crack, especially on the top.
With our collection, we do leave them open to air, then crumple newspaper to leave inside for a few days. A dryer sheet left inside will freshen it up, but those that REALLY smell just won't get better. I would never buy one that has that awful odor. I bought one to try and NOTHING worked. As we all know, the only way to get rid of mold is to completely remove it. If it remains, it will come back. Unfortunately, you can't remove it without destroying the originality of the box. You can't replace the original liner.