This is a process to get the same results as the "acid" process without, however, the latter's negative aspects, caused by the use of toxic substances.
Sand or alumina powder is sprayed onto the glassware using a compressed air device.
The impact of the particles on the surface causes microfractures that make it opaque. Sanding is marked to a greater or lesser extent by an appropriate adjustment of both air pressure and particles size.
Used mostly on flat sheets, this technique has also found application in the preparation of some prearranged drawings, by masking some of their parts.
At the end of the 30's, an extraordinary virtuosity was reached: this was the case of some extremely rare vases made at the S.A.L.I.R. glass factory, whose glassmasters actually managed to pierce the glass surface to create refined decorations having a metal-like effect.