Charles:
I came across some information that may interest you in Rosa Barovier Mentasti's book on Fuga. In the technical section at the end, she defines "acid etching." "The technique uses hydrofluoric acid, the only acid that can corrode glass at room temperature, in a wide variety of mixtures that attack the glass more or less aggressively.... A variation of acid etching is the Venetian 'corroso' technique, characterized by a surface that is similar to ice, or craquele. The surface of the glass is covered irregularly with wax using a sponge. The object is then plunged into a tank full of sawdust soaked with a hydrofluoric acid compound."
My last post had it the wrong way around as corroso is a variation of acid etching.