The special 'fabric crayons' are not permanent on cotton fabric. They are made for synthetics (for t-shirt quilts), not cotton. Regular Crayola crayons and Prang crayons have the most pigment and are the most recommended for use with fabric coloring. The fabric should be prewashed so the color adheres to the fibers better; prewashing removes all the finishes that block that adhesion. The freezer paper is used as a stabilizer on the back of the fabric to make it easier to color. Also, short strokes in one direction works best. Have fun.