My mum bought me a thingy of Textile Yarn (the brand she got is Boodles, I’m not sure what other ones exist), it’s basically like thin strips of jersey so you could feasibly use old t-shirts although you’d need a lot and you’d have to tie the strips together.
I then knitted a loose weave scarf/cowl using my arm! I used this tutorial which I found really clear so I am not going to attempt to improve upon it! Arm knitting, it turns out, it significantly easier than regular knitting, and the scarf took about 30mins. It’s not very warm but I quite like it as an around-the-house scarf, if that’s a thing?