Hi All I'm a new member and like to ask few questions
I just got my self in very good condition Hamilton
model 23 with yellow crystal .
Why yellow crystal? watch got no military markings plain SS or nickel case with low S/N P9368

Old yellowed plastic crystals are releasing gases that corrode metal parts

Pop crystal out and throw it away now

Replace with glass or modern acrylic

regards,
bb

Peter, Uscrew the crystal bezel and send it to our club member William White. He will grind and fit a new Glass crystal for a very reasonable price. To learn more, go to;

https://ihc185.infopop.cc/eve/f...6013713/m/2871042023

So the yellow crystal is original to the watch?

Welcome aboard Peter.

No, it was originally a clear plastic crystal. The yellow color is from decomposition of old unstable plastic material.

You should replace it with a glass crystal as Buster and Dave suggested or a modern plastic crystal, which will not decompose.

ok will do thank you all .