How can i adjust plastic frame eyeglasses?i was told that if you heat them up, they could be adjusted easily. but how can i adjsut and for how long?
Any suggestions will be appreciated.

The easiest way to do it is to boil a pot of water, and dip the glasses into it. How long will depend on the thickness and rigidity of the plastic material.
Go very slowly,Whenever possible, have your whole hand wrapped around the part that's not bending, as opposed to just a couple of fingers. More surface contact will mean less stress on any one given point. Be prepared to dip and bend several times before you get the fit you want.