I think I have a black card I bought specifically for transferring the vinyl to transfer paper, but I couldn't find it. Glad to know my Kohls card is good for something these days...!
This is the etching creme. It comes in this teeny bottle with a not so teeny price tag. It does go a long way, though. I put on a LOT. It says on the bottle to be careful you don't get any on your hands. Apparently it can etch (aka BURN) your fingers off! That's how it works it's magic on the glass. I was sure not to test this burning theory out...I'll just assume they are right.
I used a small foam brush and left it on for a couple minutes. The instructions say leave on for 60 seconds, but I think it depends on how "dark" you want the etching to be. After, just rinse it off with water. Again, super easy!