Smith has a different (and better) anti fog treatment than other brands. We dont use an anti fog spray that can be wiped off, we have a hydrophilic chemical treatment called 5x Anti fog that creates a micro-etched surface on the inner lens to absorb moisture before fog can form. Because Fog-X is a treatment that is actually burned into the lens, it can’t be wiped away like other anti-fog coatings.
if there are sunscreen or sweat smudges on the inside of your Smith lens, you can even washout the inside of our lenses in a sink (take them out of the goggle frame first) to get them clear again.
No matter what brand of goggle you have, you want to bring them inside at night (take out of pack or bag) to air them out, otherwise you could have some fogging problems the next day. Hope that helps