Glass versus plastic

More or less, all laboratories in life science have been moving or are moving from glass pipettes to plastic pipettes. I am not talking about the small-volume pipette tips (10-1000µl), which have been always made from polypropylene, but the so-called serological pipettes. Traditionally glass pipettes have been used, but most of the labs have been moving to the disposable type. Our lab is using the disposable type with volumes of mostly 5, 10 and 25 ml for cell culture (and occasionally 2 and 50 ml). These are made from polystyrene and I have seen the old glass pipettes being thrown away. I rescued one big batch of such totally functional glass pipettes from the waste assuming that sooner or later, we might decide to go back to glass pipettes for environmental reasons. But the glass pipettes need to be washed and sterilized, which also uses chemicals, water and energy. Maybe plastic is environmentally the better choice? I guess nobody really knows...