I have a decent collection of Contigo travel mugs for my wife’s coffee requirements. Half are natural brushed stainless, and the other half… well, they used to have various colors.
The colorful coatings are mostly gone now (dishwashers are harsh, but we’re lazy, heh 
), but I’d like her to still be able to differentiate wake-up coffee from leaving-for-work coffee. I figured I may as well try engraving the plain metal.
I had one damaged one to test with, and a quick coat of citristrip and a 30 minute wait took the remains of the color right off. I played around with it to get the hang of the rotary and my parameters, and once I had something cromulent, I threw a good one on the chuck and did this:
That’s my personal map of the trails on Mount LeConte in the Smokies (GIS data processed in QGIS, labels and decorative elements added in Inkscape).