Hi William,
I cant tell you what it is made of, its like some form of plastic/celluloid on paper. There is not a great deal you can do with these dials unfortunately although you can buy a replacement paper dial and then try some thick coats of lacquer to try and get a similar finish but to be honest I think these clocks look great with their original “grubby” dials, it adds to their character and shows their age, it just would not look right all clean and white.
Not much help I’m afraid but who knows, someone here might be of more help 
Hope you are keeping well and havn’t missed me too much, I am getting married at the end of the month so have been kinda busy
