I often don’t know what material I’m dealing with until I actually apply the heat.. Especially when I’m working with old work, I have no idea as to the content of the yarn, and whether it will melt or just burn. Out of the bits I salvaged earlier from my second year work, this one is the only one which came to anything.
The colour change is the most remarkable bit, I think there must be some natural fibre content in there for it to have scorched like that (it smells like toast). But it still contracted and then went hard.
So synthetic mix yarns can end up looking like rusty metal when direct heat is applied