His shirt wasn't made of celluloid, just his collars and cuffs. At one time, it was common for shirt collars and cuffs to be purchased separately and attached to your (collar-less, cuff-less) shirts: https://en.wikipedia.org/wiki/Detachable_collar
As for the hat, remember that hats were made of felted beaver fur. To make a hat shiny, you'd brush it -- but if you brush it the wrong way, it'll look rough and weird.
As for the hat, remember that hats were made of felted beaver fur. To make a hat shiny, you'd brush it -- but if you brush it the wrong way, it'll look rough and weird.