Since 1975, attempts have been made to protect Warsaw's historic cemeteries from total destruction. One major aspect of this project is the rescue of a vast number of cast iron and wrought-steel monuments. Workers at the Institute of precise Mechanics developed a method of preserving those monuments which consisted of a mechanical (steam abrasive) removal of corrosion products and paint layers, followed by the application of a layer of metal zinc, 1.5-2 centimeters thick, by means of spraying. (Electrochemical methods of corrosion removal were applied on small, delicate portions of the monuments.) The zinc-coated monuments were then painted with black paints.