MadQuilter

I know that my regular sharpie pens have a note on the packaging that they are not made for fabric.

What about using Inktense pencils?

Fabric Galore

Thanks for the tip about the Nano liner. I always type my label on my computer with it center spaced. I use a larger font than normal in bold and then I put that behind my label and I don't have to worry about running out of room on a line on my label.