Tinsel consists (usually) of a metallized platic sheet sliced into a "comb" and wound around a thin flexible (usully iron) wire core.
BorgCo tinsel substitutes Nitinol (memory metal) wire for the iron wire.
On removing the tinsel from the tree, simply warm it with a hairdryer or similar low-temperature heat source. Et viola ! The tinsel straightens out, and can be put back in its storage box or tube until next year, when it will emerge pristine and, most importantly, entirely free of tangles and knots.-- 8th of 7, Dec 15 2019 I was sure we had done "nitinol xmas tree" but a halfbakery search failed to find it. Perhaps it was an [Ian Tindale] or other vanished 'baker...-- neutrinos_shadow, Dec 16 2019 I thought so too.
The tinsel I'm familiar with comes in these types: long strips of aluminized super-thin plastic sheet about 1 mm wide, with no reinforcement, prone to tangling; rigid sheet metal strips about the same shape that stay completely straight at all times; icicles formed by bending sheet metal strips into helices. I don't immediately recognize the style described as prior art here, that is "wound around a thin flexible […] wire core".-- notexactly, Dec 21 2019 Without wishing to inadvertently appear to be supporting [8th], I am bound to not disagree with his description. Tinsel, as commonly construed in the United Kingdom, typically consists of a flexible twisted core (of wire or otherwise), from which thin strips of reflective foil radiate to give the appearance of a feather boa or long bottle- brush.
Tinsel was originally invented as a sort of glorified pipe- cleaner to clean the tubes in tube-boilers (as in steam engines); the reflective strips were made of bronze and were effective scourers as they were drawn through the pipes. Its adoption as a decoration seems to have started with the engineering firm of Bartolph & Greene in Stoke- Bassington, who decorated a tree outside the front of the factory using surplus lengths of the stuff.-- MaxwellBuchanan, Dec 21 2019 It wasn't surplus- it was an advertising stunt. They used offcuts for the decoration, and paid some of their workers to sing a specially composed song to a bunch of railway directors one Christmas, who were then served with a lavish amount of free food and drink*.
Imagine the scene, all those top-hatted frock-coated chaps stuffing their faces while the improptu choir sang:
"Got sooty firetubes, gentlemen ? Then brush them out, our way ! Bartolph & Greene use strips of bronze, To clean it all away ! No scratches on your boiler's pipes, So safe to use each day! Save on coal, labour, time, repairs - what joy, oh what joy ! Save on coal, labour, time, repairs - what joy ! " Of course, people liked the tune so much they put their own words to it...
*The directors, that is, not the workers. Standards had to be maintained.-- 8th of 7, Dec 21 2019 Quite so, [8th], quite so.-- MaxwellBuchanan, Dec 21 2019 random, halfbakery