I plan on sand blasting mine this summer. Was thinking on my logo but the gallon marks make sense. Maybe even other marks, like 1/2 gal or even cups. I can do good detail with my sand blaster and a practiced hand at an exacto with double layer masking tape is all that is needed. I have a fine grain sand that lets me do good detailed work and when you are done before peeling off the masking tape you can fill the sand blasted areas with marker or ink or even colored silcone rubber. No integrity problem there. I have 4 5gal carboys and 1 six gal carboy. Most are full now. But come spring, I should be able to do some tests with the 1 gal old organic juice containers to get the depth right, keeping it very shallow and even. I have etched 1/8 in deep into Aneeled glass, much harder. Also I sandblasted one of those thin glass domes you buy at the craft shop for display. It isn't hard, just time intensive with the exacto. The better your attention to detail in that stage the better your etch is. And yes both sand blasting and glass etching compound WILL show up to a hair's with of a mark. What you do with the tape after cutting it is just run over it with a finger to press down the edges and then you get no seapage.