How do I stop my sunglasses fogging up?

[Gradyville]

My sunglasses always fog up when I do sports because my nose sweat easily. Can i do something to avoid this problem?

[Graettinger]

There are some commerically available anti-fogging spray, you can have a try . Spit on them would solve your problem temporarily . But it is better for you to get a pair of sunglasses coated with an anti-fog solution.

[Graford]

I cant play in glasses, I have to wear my contacts. For my motorcycle helmet shields which I believe are polycarbonate I use straight carnauba car wax which helps with the fogging a lot. Never tried it on any kind of glasses but it works great for me year round on the bike.