In the 60s we would put vaseline on a cloth and rub into finished pari for shine just as we did to our patent leather shoes to keep them shiny - never thought to try on sinamay - test on a scrap maybe.
I was wondering Elaine how the high gloss was obtained. I recently purchased a 60s style parasisal hat and it had a lovely high gloss sheen to it. Thanks for sharing.
I have many experiences with repairing straw hats. I recommend Ronseal's red label, ultra tough polyurethane varnish (gloss). It leaves a very glossy finish to the straw hats.