I have a Scorpion EXO 1000 helmet. I've cleaned the inner sun shield a bunch of times. Take it out, clean it, put it back. I've use the S100 stuff mostly because that is what was in my bag. Sometimes it's just breath and a soft cloth.
Yesterday I went to clean my face shield and inner shield and used one of those two part cleaners that they use for electronic screens. I've used them on my sheild, on my windshield on the bike.... No problems at all
Well, this one for some reason softened up the coating on the sun shield something awful, to the point where I couldn't wipe it off. Ruined. The sun sheild felt like I could dig my finger nail into it. And regardless of what I used, I couldn't clean it off.
So, it's a $19.95 less (new shield).