+1 on J&J Baby Shampoo, I used to use spit but it does not work so well these days.
First experience with a friend who was using a brand new mask straight out the box and she used baby shampoo with no issues while I spat in mine and had a foggy bit in front of my right eye for a whole dive making me keep water in my mask to rinse the fogged bit away when I was taking photographs.
Next dive and 4 years plus two new masks later I would not use anything else, you don't need toothpaste and lighters.
First experience with a friend who was using a brand new mask straight out the box and she used baby shampoo with no issues while I spat in mine and had a foggy bit in front of my right eye for a whole dive making me keep water in my mask to rinse the fogged bit away when I was taking photographs.
Next dive and 4 years plus two new masks later I would not use anything else, you don't need toothpaste and lighters.