I really like yellow onion skins. The are easy to get, cost nothing and gives an amazing yellow.
Every time I use onions when cooking I save the skins. I keep them in a jar and I just press them down and put on the lid. My jar contains 1,5l and when it’s full with skins they weigh approximately 80gram, or less.
That’s enough to dye a fabric 90x 500cm dark mustard yellow AND to dye 90x600cm bright chicken yellow.
Here are the results of fabric no:1