I used a Sharpie oil-based paint pen with an extra fine tip to write on this glass! I just sketched my lettering and taped it on the inside of my glass and then traced! So easy!
Afterward I can bake this in the oven to try and set the ink, but I still wouldn't put this in the dishwasher afterward. I plan to use it in the studio as a vase for the flowers I'm cutting from my garden!