i use ceramic lead marking pencils- Fons & porter has one and (i think Streamline) has one- they come with different colors- green, pink, yellow, white, gray---the marks erase away, brush or wash---i've had good luck with them- fine lines- show up well & haven't had any problems with the color coming off on the thread- i've used lots of regular pencils over the years too (just like the ceramic ones because they stay 'fine-lined' are refillable) the pencil has always washed out of my finished projects- i'm surprised you had a problem- to me- pencil is the easiest markings to remove- i just wash my finished *quilted & bound* quilts and all marks are gone.