If you missed Part 1 you may want to go back and read the first experiment with the Frixion pens.
I left off showing you the red/white strip after ironing.
Here's the same strip after throwing it in the wash then putting it back in the freezer.
New piece. Freshly marked with the Frixion pen.
Washed one more time. Not even white marks on the red.
Washed, then froze. No marks.
My lesson is the frixion pens should be washed out once you iron it.
Thanks for humoring me on my un-scientific science experiment.
The bottom line is always check your pen/pencil/chalk before marking your quilt!!