I am overhauling an old low grade Elgin Pocket Watch S/N 530783 that belonged to my Great-Great Grandfather. It has a plastic or celluloid type crystal. Is this original? The plastic crystal has yellowed and makes reading the dial difficult. Is there a way to brighten or polish out the yellowed material? If it is not original could it be replaced with glass?
As far as I know there’s not much you can do to remove the yellow from that crystal. Maybe someone else up here knows a trick or two that might help. Your original crystal was glass. If you would like to replace the plastic one with glass (always nice) then you’ll find a few good sources to choose from by putting “glass pocket watch crystals” into google.
Hope this helps Steve!