You can use the water or air soluble markers. The water soluble usually have blue ink and the air soluble usually has purple. DO NOT IRON over these soluble marks or they become permanent. If you live in a high humidity area the air markers may disappear to fast for you. Have you tried using the white chalk and turn on your black light? Sometimes we forget most APQS machines come with black light. I use the gray chalk marker on most items I have to mark. Stay away from the yellow, pink and blue chalks, they do not wash out. I also use the Crayola washable markers (like you buy for kids) but test that the color I use will wash out (put it on test scrap fabric and rub out with a paper towel or wash cloth). The Crayola markers are a lot cheaper than sewing markers but as I stated test before you use on the quilt. Hope this helps.