How do you etch on dark blue glass?

Question:I am trying to etch on a dark blue bottle. I tried once and you cannot see it unless you hold it up the the light.

Answers:
Etching on glass is done either by grinding the surface of the glass in such a way that it is no longer smooth, and the rough edges show in the light, or by masking it and then applying a chemical that eats into the surface where it is not masked. I presume you are talking about the first system. Using a regular glass etching point is tough because it is so labor intensive, but Dremel makes a carbide point for this purpose. Simply draw your design on in magic marker and then grind over it with the Dremel. It works beautifully. I have done Skye Vodka bottles this way... The make cool lamps!