I recently etched designs on to pint glasses and thought I would share my wisdom in doing it... a few mistakes I made that maybe you won't!
I bought Armour Etch from Michael's and used a foam paint brush to brush it on.
I used pint glasses I found in Target for $1 each!
And you need a stencil of some sort. I used my silhouette cameo to cut a dogfish and used the outside of the design as the stencil. Here's where lesson #1 comes in - leave a LOT of extra vinyl/sticker space on the outside to block runoff cream from the glass.
Apply the vinyl/sticker to the glass wherever you want the design, make sure it is smooth and stuck down good.
Use the foam paint brush to apply the etching cream nice and thick.
Since the glasses are curved, it was going to run down the side in some manner, this is why you need a lot of extra vinyl around. The first time I attempted this I accidentally let it run off the sides while it was sitting there drying (that's what I get for doing too much at one time) and it also etched the glass in a different location... no good!
The jar says to let the cream sit for 5 minutes, I let it sit for more like 10 minutes just to be safe. Then take it to the sink and use a wet washcloth to wipe off the excess cream. Then remove the sticker and voila!