In a big container I placed a soda soaked piece of fabric and placed a number of ice cubes on top of it. I used a yellow one and two different blues.
Covered everything with a second piece of fabric and left it there till the ice cubes were melted.
After rinsing and washing these are the fabrics:
The top one was the fabric which was on top. I can see that because there are more white or very lightly colored areas.