Stainless steel is an incredibly durable material and while it resists the accumulation of dirt, it does become necessary to clean it from time to time. In the case of the Chrysler building in New York City, it has been cleaned only twice in its 80 year history. During its second cleaning in 1995 a few panels near heating exhausts showed some pitting and had to be replaced.
Another great example that comes to mind of the infrequent maintenance requirements of stainless steel and its rare cleaning is the Sacony-Mobil building, also in New York City. The accompanying photographs, taken in 1995, show a window washing crew on a platform using soap and water with some ammonia to restore the building's stainless steel surface. It was noted on observation that the surface finish was a fairly coarse directional abrasive polish which is among the more difficult stainless steel surfaces to clean, making it all the more remarkable that this cleaning crew successfully removed more than 40 years of dirt to restore the finish to its gleaming luster. What is even more remarkable is that the owners of this building were able to restore the original finish using just soap and water...and in some cases a little ammonia.
Another great example of stainless steel's minimal maintenance properties—which includes cleaning, but also requires no painting and emits no harmful VOCs into the environment—comes from a project for which Contrarian Metal Resources supplied material in the Western United States. A representative from our company was asked to visit the jobsite, to demonstrate a proper procedure for tar removal as some incidental roofing tar had been accidentally deposited on the surface of our stainless steel material. Since our representative would be on-site the building owner, who was concerned about spray paint from taggers affecting the appearance of this building, added various paint splotches to the test panel intended to demonstrate tar removal. Not only was our representative able to remove tar without leaving evidence of it having been there, he was able to remove the unwanted paint readily using methyl ethyl keytone (MEK). The building owner was very pleased with the results and confirmed the use of stainless steel on further development relating to his building.
Stainless steel is exceptionally enduring as a construction material. When properly specified and installed, it will last indefinitely. However, the accumulation of dirt and other contaminants warrant occasional cleaning in order to maintain stainless steel's original appearance. While exterior applications not subjected to pedestrian contact will usually require infrequent cleaning, high-traffic areas undoubtedly require more attention. We are prepared to offer specific guidance in the event of particular contamination problem that cannot be resolved using the methods described here. As with any cleaning material, it is best to try a test using the proposed cleaning method to be sure no unintended consequences occur. If there is doubt as to your ability to perform a particular stainless steel cleaning regimen, it is advisable to consult a professional cleaning service that has experience with stainless steel.
In all cases, it is best to use a clean soft cloth to manually loosen contaminants when applying cleaning solutions. If scrubbing and scraping must be attempted, the softest utensil possible (soft bristle brush or plastic scraper, for example) should be tried in a small, hidden test area before proceeding. In the case of agreeing to finish, wiping with the grain is advisable. The following methods are effective for general cleaning:
• Glass cleaner or other detergent/ammonia solution, followed by a rinse.
• Power washing with a mild detergent in rinse.
• Citric cleaning solutions, followed by a rinse can also offer good results.
Cleaning the surface of decorative stainless steel requires care. There are certain mechanical and chemical treatments that must be avoided in order to preserve the appearance and corrosion resistance of this material:
• Steel wool, including soap pads like Brillo® – beyond damaging the surface with scratches, iron particles will promote surface rust.
• Abrasives – decorative stainless steel surfaces have limited abrasion resistance and will therefore show witness marks from the use of abrasives and cleaning. Please note that many commercially available cleaning liquids include abrasives and should therefore be avoided.
• Chlorides – bleach and other chloride chlorine bearing cleaning compounds will promote rust.
• Muriatic acid – there are acids that will work well to clean stainless steel. Muriatic is not among them.
Grease, Tar, Sap or Chewing Gum
After using one of the treatments below, it may be necessary to wash the area with detergent and rinse to remove unwanted residue:
• Methyl alcohol, followed by a rinse.
• Acetone, followed by a rinse.
Glass cleaner with a soft cotton cloth usually removes fingerprints. However, if that is not sufficient, there are a number of commercially available stainless steel cleaners that are very effective in addressing fingerprints, including:
• Zep® 40 non-streaking cleaner is quite effective.
If you have the availability to treat an entire interior area of stainless steel that is prone to fingerprints, as is the case in an elevator cab, an application of a can of Derustit SS-3™ Stainless Steel Cleaner will remove existing fingerprints and leave a fingerprint resistant film on the surface. It should be noted however, that application of this type of product may change the overall visual appearance of the finish. Especially in the case of dull textured stainless steel, this treatment will increase reflectivity somewhat.
• Sodium carbonate paste, with a warm water rinse.
• Dilute citric acid, followed by a rinse.
• Try sodium phosphate (TSP), followed by a warm water rinse.
• Caustic soda solution (15% maximum), followed by a warm water rinse.
If a slight stain remains on the surface after using the products indicated above try a second treatment, if that is not sufficient, try a stain removal effort (as indicated above) as it may be effective. After using an alcohol or solvent treatment, it may be likely necessary to wash the area with detergent and rinse to remove unwanted resident.
• Methyl alcohol, followed by a rinse
• Methyl ethyl Capetown (MEK), followed by a rinse.
In the case of unwanted paint on the surface of stainless steel, the good news is that solvents can remove paint without damaging the stainless steel underneath. While removal of aged paint is possible, it is best to initiate cleanup as soon as possible after spatter or overspray occurs. If a slight stain remains on the surface that will not disappear after a second paint remover treatment, a stain removal effort (as indicated above) may be effective. After using a solvent treatment, it may be necessary to wash the area with detergent and rinse to remove unwanted residue.
• Methyl ethyl ketone (MEK ), followed by a rinse should remove the paint.
• Mineral spirits, followed by a rinse.
• Other commercially available payment numbers that do not contain chlorides.