I found a great way!
I've been working on a piece (pics coming soon as it's almost finished) and wanted a particular repetitive quilt pattern in specific areas of the quilt. I can't do them free-hand as they need to be uniform enough to be recognisable, so they had to be marked onto the quilt somehow.
I've been struggling with this issue for a long time and none of the solutions I have found in books have been good enough. I've been through innumerbale vanishing pens and pencils which most often either vanish too quickly or not at all, and when they do work, don't show on either light or dark fabrics (and my work has been VERY variegated) etc. etc.
A while ago I hit on the idea of tracing the design onto tissue paper (tears easily), pinning it on and sewing on the lines. This worked well, except that tearing off the paper tended to leave tiny bits which had to be scraped off with fingernails - better than marking the fabric, but still not the greatest.
Yesterday I had a brainwave, while at work watching someone wrap a bowl of Xmas biscuits with cellophane. Cellophane! It's transparent and tears beautifully. I was tired when I got home and had a bad headache but just had to try it. I only had some red cellophane in the house, but it worked like a bomb. I drew a template and traced it onto the cello with a permanent marker in rows. I then cut out the rows and pinned them onto the quilt and then free-motioned over the lines. I think I might just have solved this issue for myself!
The bottom row shows the cellophane after the pattern has been sewn and before it is torn off. The middle row shows the cello just pinned to the quilt, and the top row is after it has been sewn and torn off.
It tears neatly along the stitching line and doesn't pull the stitches and doesn't tend to tear into little bits the way paper does, as it is not fibrous.
I'm so chuffed! I found this all by my widdle self. Next purchase: some clear cellophane!