Review on Clover 4710 Pen Style Chaco Liner in Blue by Heather Shaw

I bought this to mark quilting fabrics. It is suitable for marking lines that are not visible or for things that you will wash after sewing. I was hoping to use this to mark the lines of the quilt on the quilt. Since I prewash all fabric before quilting, I do not wash the finished quilt. In testing I found that I couldn't just brush the chalk off, and even dampening a cloth and wiping the chalked area with it didn't clean the chalk. It really came off when I actually put the marked fabric in the washing machine. It's very easy to use, so I use it to mark the wrong side of the fabric or where it's not visible. I'm going to use thick white school chalk to mark the top of the quilt. Which is easy to wash without washing;