Linda, I'm so embarrassed,
I know now why that blue pen did not want to wash out! I looked more closely at the pen I used (for only part of the block) and it's
NOT EVEN A FABRIC PEN! I think it originally came with a wipe-off board or calendar. Somehow it made it into my sewing supplies! My other blue pens seemed to be drying up, so I switched over to that one. My, it made a wonderful, easy-to-see marking! But I'll never use it on fabric again, I can tell you! I used: cool water, lots of it; Dawn dish soap; lots of hydrogen peroxide; color-safe fabric bleach; then I went to Wink rust remover! I am very fortunate I was able to lighten it as much as I did. So in other words, I can't complain to the manufactor on this one! :roll
But I do thank everyone for their nice comments!