In order to remove the tint from eyeglasses, first you should determine the types of lenses in the glasses because it is necessary to know the kind of lens prior to removing the tint from it.
There are usually three types of lenses which are used in the eyeglasses; plastic, polycarbonate and glass. Cover the lens of the eyeglass with the help of a cloth towel and then tap it gently with either the edge of a spoon or your finger nail. If the lens sounds plunking and dull then it is possibly plastic. But if it makes a more tinny sound then it is polycarbonate. On the other hand, glass has a more familiar sound like a tap on the wine glass.
However, be careful while tapping the lens because a hard knock can either crack or chip it. After concluding this test, if you find out that your lens is not made from glass then the tint can be removed from the eyeglasses.
Now take your plastic or polycarbonate lens to an optician or eye doctor so he or she can lighten the tint. In case you are still not sure about the type of lens in your eyeglasses then an optician or eye doctor can determine it for you.
As far as the removal of the tint is concerned, optical retail stores usually have specific units for this type of work where they employ a special type of chemical to the lens to remove the tint. However, this procedure requires time, so the optician may keep your eyeglasses overnight or for a day in order to remove the colour. But the time taken may vary as it depends on the age of the lenses. An old lens takes more time to remove the tint.
The other option to remove the tint from the eyeglasses is to contact an online optical laboratory that removes tints. You will find several such online optical laboratories that can provide assistance in this regard. However, online optical labs keep lenses for more period than regular opticians and doctors do.