crayola washable markers -

https://www.quiltingboard.com/main-f...e-t304348.html

https://www.quiltingboard.com/main-f...q-t299935.html

Here are two examples of quilts i have marked with the crayola markers - all of the markings came off when I put them in the machine.

I haven't had any complaints with the Frixon pens I've used. I also use a white mechanical pencil from Fons and Porter on darker fabrics. It rubs out with a touch of a damp cloth. There are many options out there. Use what works for you. I've even used soap slivers with a sharp edge and they worked fine, too.

You didn't say what you're trying to mark. If it is straight lines across the quilt you can use painter's tape or contact sticky shelf liner. Don't leave them for a long time though.

When I just want to make a tiny dot or so on a quilt I use the water soluble blue fabric pens or tailor's chalk. The chalk should come out completely although you may have to brush it to completely "erase" it if it's a high contract color to the fabric. Use a brush that has a little stiffness to it - kind of like the brushes they sell for cleaning the bobbin area of your sewing machine.

I've used a thin sliver of soap to mark patterns, & painters tape for straight lines that didnt follow block lines. Both worked well.