Hi Pete
Indeed this rejuvenator is a highly flammable product with some pretty nasty side effects in inhaled or used in a poorly ventilated enclosure. That's why you must follow the warnings and directions on the can and use with a good measure of common sense. Some platens are simply too hard for the rejuvenator to have any effect, but if the platen specs out at 96 Shore-A or lower, a few applications of this product can drop the Shore-A number by a couple or three points.
Peter Short from J.J. Short of Freeport, NY indicates the ideal platen hardness for a manual typewriter is 88 to 90 on the Shore-A scale and 95 for an IBM Selectric. Smith-Corona used to make a brass platen for use on their electric typewriters when 6 or more carbon copies were being made at a time. I'm figuring that would take some serious striking power to punch out 10 carbon copies, no matter what kind of typewriter you were using. All the best,
Sky
We humans go through many computers in our lives, but in their lives, typewriters go through many of us.
In that way, they’re like violins, like ancestral swords. So I use mine with honor and treat them with respect.
I try to leave them in better condition than I met them. I am not their first user, nor will I be their last.
Frederic S. Durbin. (Typewriter mania and the modern writer)