Small container of warm water with some Dawn dish soap. Stir the soap in by hand but be careful not to make a bunch of soap bubbles. Dip your glasses/lenses in and let them drip dry. DO NOT wipe them off. The dish soap makes a thin film that prevents fogging. It works really quite well. Only issue is if you sweat a lot from your head and you splatter/drip on your glasses you can’t wipe them off or you will wipe off the anti fog film.