Tutorial: New life to your leftover yarns

Failed experiments at the end!
Card your leftover/scrap yarns into spinnable fluff and spin them into new yarn!
My leftover jar included:
Wool +++
Polyamide +
Acryl ++
Alpaca +++
Polyesters (+/-)
Cotton -
Bamboo -
Linen -
Silk +
Handspuns (--/+)
Cable plied merino ---