At the echidna convention earlier this year the ladies from sewing revolution spoke about a pen that disappears if you iron on it. I finally got around to looking for these pens. I got them from Big W. They are brilliant, you can really clearly mark you placement position then when you are finished the embroidery just it it with the iron and the mark is gone. I got 3 different colours. The mark won't come back unless you cool it to -20 degrees celcius. I think this is a must in and embroidery tool kit.