Have you seen this?

Here's a cool new tool!
This Sewline Trio mechanical pencil has 2 ceramic leads - black and white, plus a tracer point for tracing patterns, and a built in eraser.
Specially formulated leads give a clear, fine line on fabrics, which is easily removed from most fabrics with the special Sewline Eraser or by dabbing with a damp cloth or washing. Simply rub off with the eraser or dab off with a damp cloth. The refillable lead colors are created to fade under sun light. We have black, white, and yellow refills. Those light colors are perfect for marking quilting, stitching, or sewing lines on dark fabrics.
Just twist the barrel to change points.