Nothing conventional works. I have tried the detergents, Johnson's Baby shampoo, toothpaste, Nofogs, they are all ineffective on a new mask, one shot deals at best. Freediving, I swam back to my boat four times to wash my mask with baby shampoo. The treatment was good for 1/2 hour. Do the slow burn as mentioned above or try this: Scrub the lens with Starbrite liquid rubbing compound and follow up with detergent or alcohol. Rinse and spit in the mask and rinse again. As mentioned, breath into the mask. If the mask does not fog it should be good for life although a spit rinse should be done at the beginning of the diving day. I know that each of the posters is adamant that their method works but virtually all do not work on the newer masks of certain brands. There is a substance on the lens which must be removed and does not respond to any conventional treatment nor to several innovative approaches that I have tried such as powerful solvents. I don't know why the rubbing compound is effective. In any case, the burning is quicker and easier but whether it will work on all masks I don't know. Ran out of masks to test.