Kärcher, in cooperation with the National Park Service, recently had the honor of cleaning the presidents' heads on Mount Rushmore in South Dakota. The restorative cleaning work was carried out as part of a culture sponsoring project. The aim of the project was to remove lichen, algae, moss and other organic stains that could damage the underlying rock by way of bio-corrosion. The cleaning kicked off on Independence Day (July 4) and required a little more than three weeks to complete.

The cleaning was performed purely with water, without any chemical additives. Five diesel-powered Kärcher hot water pressure washers cleaned the granite surfaces with rotary nozzles using Kärcher's patented DirtBlaster technology, which increases the effective cleaning pressure by up to 50%. The use of hot water will delay any recurrence of growth on the rock sculptures. Following the cleaning trials conducted earlier in April, two independent scientific experts deemed this process to be the most effective and most gentle on the material.

Sculptor Gutzon Borglum's giant heads of American Presidents George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln were carved between 1927 and 1941. They are about 60 feet high and, along with the Statue of Liberty in New York, probably the best known monuments in the United States. Mt. Rushmore is located near Rapid City in South Dakota.

In the past 20 years Kärcher has carried out some 80 cleaning projects on the world's greatest historical monuments. For example, the company gently and expertly cleaned the Brandenburg Gate in Berlin and the Statue of Christ in Rio de Janeiro in 1990. The Colonnades of St. Peter's Square in Rome were cleaned in 1998 in the largest facade cleaning project ever undertaken on a historic building. Two years ago Kärcher specialists removed harmful layers of dirt from the more than 3,300 year-old Colossi of Memnon in Luxor, Upper Egypt.

Kärcher USA is a wholly-owned subsidiary of Alfred Kärcher GmbH & Co. KG, a family-owned company based in the town of Winnenden, near Stuttgart, Germany. Kärcher is the largest manufacturer of pressure washers in the world, with more than 5,600 employees around the globe. Currently celebrating its 70th anniversary, the company has sold more than 60 million units worldwide and holds more than 360 patents.

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Kärcher high-pressure washers were used to remove lichen, moss and other stains from the presidents' heads on Mount Rushmore. In this view Thorsten Möwes, applications technician and Kärcher specialist for restorative cleaning, is working on Thomas Jefferson's chin.		The presidents' heads on Mount Rushmore were cleaned solely with water using Kärcher's high-pressure washers. In this picture Thorsten Möwes works on a test area.