You asked if the elves used polyester…
They certainly did ! …To weave the cloaks of Lorien. Also Sam's rope was twisted from a special variety of Polyester called in Sindarin 'poliestel', which in the tongue of the Noldor was 'pulisilarel'. The element for 'star' is obvious to anyone learned in Elvish linguistics, however the element 'pol' < 'pul' is unclear. I am personally of the belief it is cognate with the ancient Valinorean word for 'sheen' or 'glaze'. Hence 'polyester' could actually mean (and probably does) 'Star Glaze'. The Men of Numenor never learnt the craft so the name in Adunaic has been lost. And of course the Orcs didn't wear it, but nevertheless called it 'ghakhkrap bhaghkul'. Propriety forbids translation here. But knowing Orcs, as you do, I'm sure you could hazard a guess.

We in the 20th Century (just hope you've all prepared for Y2K) accredit the 'discovery' of the fibre to Mr Polyester. However, Mr Tolkien's work on Elvish philology and the Great Middle-earth medio-velar and palatal consonantal shifts of the Fourth and Fifth Ages has revealed its true origin. For that alone we are forever grateful.