Hi Tasty
Have been checking my Shannon lush books and it depends on the type of pen. This is for ball point pens
"Ink stain on fabric
What to use: Milk, detergent, water;, or dry cleaning fluid, cotton ball, talcum powder.
How to apply: Rot the milk by leaving it in the sun until solids form. The time this takes varies according to the weather and the age of the milk. Place the solids on the stain leave until you see the ink start to rise up in the solids, then wash the solids out using detergent and water. You can also use dry-cleaning fluid applied with a cotton ball on either side of the stain. If you can't get underneath the stain, sprinkle talcum powder over the dry-cleaning fluid to absorb it"
It is also mention in another of her books to use methylated spirits, or white spirits for permanent markers. Hope this may help.
Marie