spit and seaweed or moss..ya know that greeish grassy watery stuff ...that works very well...spit in the mask woosh it around and use the moss to swoosh the spit..rinse. Then soak our warm face. If no moss no problemo just swoosh the spit and rinse
One of the biggest fog problems is a warm face...cool off your face befor you dive. that will help reduce the fog or condensation in the mask....Warm face cool mask...or cool face warm mask= fog-faced-mask-dive guy.
Keep your mask out of the sun or heat. Keep your face cool with a cool moist towel.
A trick I do is before a dive, I fill the mask with cool water after I did the spit and rinse. Just befor I dive I wipe my face dry and I put the mask on. Never fog again.