I bought one after trying it at a quilt show years ago. The only fabric I could ever get it to show properly on was batiks. I do prewash my fabrics and I don't know if it would work better on unwashed fabrics or not. I gave it all away to a quilting buddy.... asked her a few years ago if she had tried it.... no... but she still had it, thinking she might
Sorry for your frustrations and hope you can get it to work for you.