What about the fog of ski goggles?
Use your tongue to lick the inner mirror, which is said to be a professional athlete. The advantage is that there is no cost, that is, take and use is very convenient, shortcomings, needless to say.
Clean water rinse, dry after endoscopic face a few drops of tableware detergent, do not add water; let in the mirror with (not hand rub), a detergent placed several hours or overnight, then wash in slightly to no bubbles can. This treatment can generally be 2-6 hours tube.
Apply medical vaseline to the inner mirror; or clean the surface with fresh egg white, then use it after airing. The disadvantage is that it is easy to accumulate dirt after 1 or 2 months.
