You can evenly apply the soap on the lens, then use cloth clean it, it can have an effect to prevent fog. But the effect is not very well. You can buy anti-fog water in the optical shop, it has the function of cleaning, decontamination, frost prevention, anti-fog, and it has not stimulation to your skin, and can not corrode to lenses. The effect can last 1-3 days. You can also make anti-fog water by yourself, mix 30 ml glycerol and 10ml liquid soap, then add a few drops of turpentine, stir them well. You can apply it on the lens, and then use cloth to wipe it, which can help you prevent fog 3-4 hours.
You can clean the glasses by yourself easily. The stuffs you need: a bowel of warm water drops of body solution or detergent and a piece of glasses cloth or 100 percent cloth. Wet your glasses in the bowel of warm water at first. Then drop some body solution or detergent on the lenses on both sides, and then wipe them with hand carefully. Then swirl the glasses with the water and dry them with glasses cloth or 100 percent cloth at last.
You can paint your glasses with a little Vaseline or soap, and after a while, wipe the glasses with a clean and soft cloth gently, in this way, your glasses will be clear. Also, there is another way for you to choose: Buying a bottle of special protective liquid in some glasses store, it can help you to clean out and antifog effectively. I hope the above information can help you.
The principle of cleaning the foggy glasses is to remain the glasses bright and clean, not contaminated with grease and avoid scratching the lens. You can use a mild soap or special cleaning agent to clean it, wash it with water and then dry it with lens paper or soft tissues. Many people pick up the clothes or handkerchief to wipe the lens. This is a bad habit, because the rough material can easily scratched lenses. To clean frames between the slit, you can use a soft old toothbrush to gently scrub it and to remove the grime.