Replying to Can you touch the inside part of a prizm lens?

I just wore my brand new Flight Deck XM's out for the first time and there was a tiny little speck on the inside that I couldn't get off. I licked my finger and rubbed it a bit, then dried it with my goggle bag. I just randomly heard a goggle tech say never touch the inside of your goggles with your fingers. That seems a bit extreme to me, but wanted to get your guys' opinion and what you've heard...

It worked and got the spot out, FYI.