TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The medium further contains at least an inorganic mineral acid and one or more phosphoric acid or its salt (which is decomposed by heating), which acts as etching or doping components. The etching medium is washed with water after the etching process. The etching process takes place at 320-390, preferably 200-450degreesC.Preferred Process: The process further comprises applying the etching medium on the inorganic-, glass-like-, crystalline- surface, optionally doping with the solvent or its mixture by heating and removing the solvent.Preferred Components: The inorganic powder (greater than 5 microns, preferably 1-10 microns) is fine particulate plastic powder of polystyrene, polyacryl, polyamide, polyimide, polymethacrylate, melamine-, urethane-, benzoguanine-, phenol, silicone- resin, micronized cellulose, fluorinated polymer (polytetrafluoroethylene or polyvinylidene fluoride) or optionally inorganic particle of aluminum oxide, calcium fluoride, boroxide, sodium chloride. The amount of the inorganic powder; corroding component; thickener; organic and/or inorganic acid; solvent; thickener and additives is 1-80, preferably 20-40 wt.%; 12-30, preferably 5-15 wt.%; 3-20 wt.%; 0-80 wt.%; 10-90 wt.%, preferably 15-85 wt.%; 0.5-25 wt.% and 0-5 wt.%, respectively. The surface of the glass is of calcium, sodium, aluminum, lead, lithium, magnesium, barium, potassium, boron, beryllium, phosphorus, gallium, arsenic, antimony, lanthanum, scandium, zinc, thorium, copper, chromium, manganese, iron, cobalt, nickel, molybdenum, vanadium, titanium, gold, platinum, palladium, silver, cerium, cesium, niobium, tantalum, zirconium, yttrium, neodymium or praseodymium. The mineral acid is of hydrochloric-, phosphoric-, sulfuric-, nitric-, optionally 1-10C-organic- acid of alkyl carboxylic acid, hydroxy acid or dicarboxylic acid. The organic acid (with pKs value of 0-5) is formic-, acetic-, lactic- or oxalic- acid. The solvent is water or multi-valent alcohols such as glycerin, 1,2 propanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 2-ethyl-1-hexenol, ethylene glycol, diethyleneglycol, dipropylene glycol, ethyleneglycol monobutylether, triethyleneglycol, triethylene glycolmonomethyether, diethylene glycolmonobutylether, dipropyleneglycolmonomethylether, ester of (2,2-butoxy-(ethoxy))-ethyl acetate, carboxylic acid ester such as propylene carbonate or ketones such as acetophenone, methyl-2-hexanone, 2-octanone, 4-hydroxy-4-methyl-2-pentanone or 1-methyl-2-pyrrolidone. The thickeners are cellulose or its derivatives; starch or its derivatives; xanthane; polyvinylpyrrolidone; acrylate polymers or vinyl polymer. The medium exhibits a viscosity of 6-35, preferably 15-20 Pa.s with a shear rate of 25 second1 at 20degreesC. The fluxing agent (0.05-25 wt.%) is dimethylammonium chloride, diethylaminphosphate, diammonium-hydrogen-phosphate, urea, magnesium stearate, sodium acetate, triethanolamine hydrochloride or oxalic acid dihydrate.