This is a new one on me. I am looking at a Waltham pocket watch, circa 1940. Cosmetically it's way above average; needs a mainspring and we'll see what else later. There's an outer case with a plexi that's totally shot; the watch's own glass has a few scrapes. So I thought I'd see if a little Polywatch would bring it up before I went hunting for the right size replacement glass. Only, instead of cleaning up, it became sticky, with a strong menthol smell and then just clouded over. Suddenly the glass feels very brittle and definitely needs to be replaced now. Has anyone seen this? Is it an older type of plastic that really doesn't like Polywatch? Is it decades of an owner smoking methylated cigarettes and some strange reaction? Picture tax: Adjusted for temperature and three positions With a clear pheon on the back of the Keystone case.