It kind of reminds me of making mud pies with dandelion pesto (although I didn't call it that as a child)...
The experiment:
Two marigolds, one cup of boiling water poured into each container, 2 pieces of the same cotton fabric...except one was soaked in an egg white (found suggestion for eggs in one of India Flint's books) for approximately 24 hours. Left outside soaking for the same amount of time on a day that reached 81 F. The containers were covered with a lid but not air tight.
After soaking for about 10 hours they looked like this.
No noticeable differences between the two.
I wonder what they will look like after washing and if they will fade at different rates?