Three methods are available.
Sandblasting which is easy if you know someone with the gear.

Nope :-(

Hydrofluoric acid which is deadly and should be steered clear of.

I knew there was an acid that did it, but couldn't remember what it
was - it's probably also a biatch to get hold of...

And a harmless chemical that attacks part of the glass and gives a
fine etch to it. Sadly I don't remember it's name. Sorry

Some of the DIY shops do an "etch" spray, but I suspect it's a plastic
sprayover layer, rather than a proper etch solution...