Matte Black on Teflon Knobs

[W3XWT]

I'm posting here as there really isn't a category for this problem.

I have a 2006 Hummer H3, that for a variety of reasons, still has the stock GM "Monsoon" sound system.

Unfortunately, the knobs and switches seem to be made out of something similar to Teflon(tm), and the original matte black paint has long since worn off.

I've tried permanent black marker, black matte model paint, black nail polish (bummed off my daughter), all to no avail.

Has anyone sucessfully repainted these knobs and had teh paint stay for more than a few months?

Thanks!

John
W3XWT/6