I am planning to make a wall hanging for my son's teacher that is having to retire at the end of March. It is unexpected and for medical reasons. So I wanted to make a tree and have different color fabrics for the leaves. And then I am going to let the kids sign their name on the leaves. What type of markers should I use that won't wash out or fade? I am planning on using the raw edge applique technique and thought I could wash it when I finished sewing so it would ravel out a little. Any bits of advise??? Thanks!!