Once, I ruined a blouse because the lines I made to guide decorative stitching did not wash out. I used colored chalk and a holder for that catastrophe. Ever since, I have been on a quest for the perfect marking tool. Air and water soluable markers make nice clear marks, but for some unknown reason, mine dry out rather quickly. Even though I'm careful to replace the cap, I've seldom had one that lasted more than two or three months. Chalk wheels are good, but it's hard to make small, precise marks with a wheel. Good old tracing paper and tracing wheel are fine for marks on the inside of garments - just in case the paper is wax-based and won't come out if you iron over the marks. And, I still have nightmares about Cidell's experience with orange wax chalk.
I read a tip about using Crayola erasable colored pencils to mark fabric and a fabric eraser to remove the marks. I've been using them quite successfully for several months. (NB Do not use the Twistables - the eraser makes a darker mark than the pencil. What a mess!) I like the ease and maneuverability of using a felt tip marker on fabric. Even though I was happy using erasable colored pencils, I tried washable markers. The marks were bold and visible, but were they truly washable?
I conducted a little experiment (on a day when I had too much time on my hands). I used a piece of gray cotton broadcloth and marked with the washable markers and erasable colored pencils. It was much easier to write with the markers - they glided over the fabric like a dream – just like writing on paper. The pencils dragged and skipped on the fabric causing gaps.
Then, I washed the cloth by hand using bar soap. The erasable colored pencil washed out almost completely. If you look carefully (click to enlarge), you can see traces of the purple marker still on the cloth. (I used a regular colored pencil to label the samples.)
The results of my experiment were not new or earth-shattering. Both the erasable pencil and the washable marker washed out without special laundering. My quest taught me there is no perfect marking tool. It's always best to test first. If I'm unsure about using any kind of marking tool, I use thread tracing.