I agree with Bill.
However, I'd be a bit reluctant to heat treat the 'Satin' variety of duck scales. Those scales are usually clear celluloid and most apt to degrade (versus colored celluloid).
Being an heirloom and most likely from the 'cellulid era', Heat might be the end of them.

I know this is not much help, but is a bit of caution.

C utz