Celluloid was one of the early plastics. Combs, toothbrush handles, and even Panama hats
were made of it. But it was cellulose nitrate, that can also be a dangerous explosive.
Celluloid was also early film base, and some X-ray departments had stored films cause
catastrophic fires. So film base was changed to cellulose acetate. But then I no longer
could make glue for model airplanes by dissolving toothbrush hands and film in amyl acetate.
Also, some of the celloid Panama hats were ignited by careless smokers, and cause horrible
scalp burns. Jokes were made about it, but it wasn't funny to victims.