Most toothpastes and Soft Scrub also work well. For defogging before each dive, spit is not adequate for modern silicone masks. Baby shampoo also works with less irritation. Both are inexpensive, readily available and useful in other ways. Leave gloves off until after mask is on so you can use fingers to assure no hair or the lip of your hood is under the mask skirt, preventing a good seal.
Masks leak for reasons other than poor fit, including being adjusted too tightly.
The purpose of the strap is to hold the mask in place, not to provide a watertight seal. What to Buy Dacor has earned a good reputation for masks of lower volume that fit the smaller or narrower face. For those divers who may be concerned with claustrophobia, clear or white silicone skirts that let in lots of light, and side windows may help, though some divers are distracted by the distortion of side windows. The snorkel should point up when your head is down in the normal swimming position and should be at least several inches above your head. Modifications Snorkelers with braces or bands on their teeth or an unusual bite may need to modify the snorkel's mouthpiece by using a razor blade or nail file to carefully remove material that rubs them the wrong way.