I came across a thread from my Garrison's forum that also suggests toothpaste. I have used the shaving cream method on my snorkeling mask while diving and it works so I would assume it would also work for this situation. Doesn't hurt to try and a heck of a lot cheaper then and anti-fog product. I have not used the toothpaste method but the contributor did say he used it for both diving and on TK lens.
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