[Arran]

Quote Chas "What happen during the rewind of the Grunow was the removal of a cellulose acetate primary/secondary liner and replaced with thin plastic film. It was that liner than caused corrosion to the primary, the bottom layer.

I do not advocate placing an entire Philco chassis into an oven because a chassis may have coils wound with the cellulose plastic liner. Cellulose acetate is very flammable, that could be a disaster!"

Chas;
 You have the right thought except for one detail, cellulose acetate is NOT the volatile and flammable form of celluloid, it's it's much more dangerous cousin cellulose nitrate. Cellulose nitrate is the main ingredient in gun cotton, and was also used in the production of early motion picture film, which is chemically unstable like many other volatile substances. It was also used to make artificial silk, eyeglass frames, and billiard balls, until the dangers became obvious, such as two nitrate based billiard balls slamming together and exploding in flames. Cellulose is reacted with nitric acid in one, and acetic acid in the other, the nitric acid process isn't used in any cellulose based products anymore, except for some ping pong balls made in China, everything else, photographic film, acetate sheets, and rayon are made with the acetic acid process now, it is not volatile and does not go gummy and leach corrosive byproducts, nor explode into flames, though it will still burn if held to a flame.
Regards
Arran