Burdensome school work result in millions of near – ssighted teenagers, to most of them, glasses will go with their eyes during the whole lives. Look at the increasing number of glass-wearing individuals on the earth, do they have any idea that how to clean their glasses? What people know is wiping lens with cloth or paper, but what they do not know is scientific methods I will introduce as below. The most convenient method is using detergent-- Liquid soap, shampoo, lotion and bath gel can be all used—and water, you can do it at home yourself.   Firstly, run water over glasses, get rid of the dust on the surface; Secondly, Take proper amount of detergent in hands and rub until foaming, shampoo and bath gel is most strongly recommendated because oiliness will left protective film on glasses.   Thirdly, coat The foam to both sides of lens, and wipe them back and forth with middle finger and ring finger, which offers softest force; Fourthly, flush hands and glasses with thinned running water, in case that water splashes to other side of lens; Finally, use the index finger to erase the residual water drops at the bottom of the lens edge.   Isn’t that operation easy? One standard that you have done everything correctly: there is no water drop left on glasses.   The other way to clean glasses is using professional equipment, Ultrasonic clearing machine. The machine uses ultrasound (usually from 20–400 kHz) and an appropriate cleaning solvent (sometimes ordinary tap water) to clean delicate items. Almost all optical stores have ultrasonic cleaner, and allow everyone to clean his glasses for free. A professional will help you operate the cleaning. If you've got time and a optician's nearby, you can try it.   Besides, you can buy one ultrasonic cleaner at home, it can be used to clean jewellery, other optical parts, watches, dental and surgical instruments, fountain pens, industrial parts and electronic equipment, which are all difficult to clean.   Following Attentions need to be known about glasses cleanliness.   It’s horrible to wipe off lens with dry cloth, because tiny dust on the surface will scuff lens badly when you wipe it drily, especially seriously to resin lens.  Moreover, organic solvents, strong acids and bases are not allowed to touch the glasses, for fear of affecting the smoothness. Avoid high temperature, which causes expanding with heat and contracting with cold. The last but not the least, only professional lens cloth can be used.