Onion skins are a readily available and lovely natural dye, easily accumulated in your own kitchen or you can ask grocery stores or restaurants. The resulting colours are a range of golden-yellows and oranges.
The more you have the better! I usually boil the skins for 30-40 minutes, add the fabric or fibre and keep warm for about an hour and then allow to cool in the bath before rinsing.
This scarf was knit with yarn dyed with onion skins. I used an alum mordant and got a rich golden colour.
The scarf is square and knit using large needles and a drop stitch pattern of:
2 knit rows, 1 knit YO2 row, 2 knit rows, 1 knit YO2 row, 2 knit rows, 1 knit YO1 row, and repeating.