The pen I used was the Fons and Porter washable graphite pen.
Time to get scientific. I have plenty of fabric so I'll make a new sandwich, mark it up and do FMQ on it as before. When I am finished, I will cut the sandwich into a number of pieces and test the following
Agent
Oxyclean Soak in Oxyclean and cold water
TideTo Go
Mr Clean Magic Eraser
Marking pencil Removal
Restoration
Milk
White Eraser
Clorax Stain Buster and Color Booster
Rubbing Alcohol/DW soap/water 6 TBSP isopropyl alcohol + 2 TBSP water + 2-3 drops liquid DW soap
Synthrapol
H2O2 plus Dawn 2 parts hydrogen peroxide to 1 part Dawn. Use soft toothbrush
Will post the results so we can all learn something (hopefully). yesterday, I bought all the ingredients, Oxyclean, Tide to Go, Clorox, alcohol, hydrogen peroxide, etc. The cashier asked me if I was doing some serious laundry!!