Stainless Steel Care & Cleaning

This manual provides care and cleaning instructions for stainless steel countertops, cabinets, sinks and other stainless steel products. This manual is not comprehensive and is intended only to be a supplemental guide. For detailed information on the products and chemicals used for cleaning stainless steel, please contact the manufacturer.

Care of Stainless Steel

Stainless steel products provided by CFI. have a directional #4 brushed finish. This finish is produced using a very fine abrasive cloth. Any mechanical damage such as dragging heavy equipment across the stainless steel surfaces will cause noticeable scratching. Scratches can generally be repaired (see p 9).

Pitting/corrosion of stainless steel can be caused when carbon steel products are allowed to remain in contact with the stainless steel in the presence of moisture – for example, leaving steel wool pads in the bottom of the sink, or metal flakes from drilling or machining operations allowed to remain on the stainless steel.

Stainless steel can also be damaged by exposure to acids. A partial list of reagents that may cause staining and damage to stainless steel is provided below. Contact CFI for more information or a complete list:

• Silver Chloride
• Sodium Biflouride
• Sodium Chlorite (Type 304 only, Type 316 OK)
• Sodium Hypochlorite
• Stannic Chloride
• Sulphur Chloride
• Sulphuric acid
• Trichloracetic acid
• Uranium Trichloride
• Chlorosulphonic acid
• Ferric Chloride
• Ferrous Chloride
• Ferrous Iodide
• Flourine
• Hydrochloric acid
• Hydrobromic acid
• Hydrofluoailicic acid
• Hydroflouric acid
• Iodine

If damage or staining occurs, the surface finish may be repaired by neutralization and cleaning or by following the scratch removal method outlined on p 9.

Cleaning Stainless Steel

Stainless steels need to be cleaned for aesthetic considerations and to preserve corrosion resistance. Stainless steel is protected from corrosion by a thin layer of chromium oxide. Oxygen from the atmosphere combines with the chromium in the stainless steel to form this passive chromium oxide film that protects from corrosion. Any contamination of the surface by dirt, or other material, hinders this oxidization process and traps corrosive agents, reducing corrosion resistance. Thus, some form of routine cleaning is necessary to preserve the appearance and integrity of the surface. Stainless steel is easily cleaned with many different methods. It thrives with frequent cleaning and, unlike other materials, it is impossible to “wear out” stainless steel with excessive cleaning.

TYPES OF SURFACE CONTAMINANTS

Dirt – Like any surface that is exposed to the environment, stainless steel can get dirty. Dirt and soil can consist of accumulated dust and a variety of contaminants that come from many sources. These contaminants will vary greatly in their effect on appearance, corrosion resistance, and ease of removal. While some may be easily removed, others may require specific cleaners for effective removal. It may be necessary to identify the contaminant or experiment with various cleaners. Usually, warm water with a gentle detergent is sufficient. Next in order are mild non-scratching abrasive powders such as typical household cleaners. These can be used with warm water, bristle brushes, sponges, or clean cloths. Carbon steel brushes and steel wool should be avoided as they may leave particles embedded on the surface, which can lead to rusting. For more aggressive cleaning, a small amount of vinegar can be added to the scouring powder. Cleaning should always be followed with rinsing with clean, warm water. To avoid water spots left by mineral solids in water, wipe the surface completely dry with a towel.

Fingerprints and Stains – Fingerprints and mild stains resulting from normal use are the most common surface contaminants. Fortunately, these usually only affect appearance, and seldom have an effect on corrosion resistance. They can be removed with a glass cleaner or by gently rubbing with a paste of soda ash (sodium carbonate) and water applied with a soft rag. Once again, this should be followed by a thorough warm water rinse.

Shop oil and Grease – Shop oils, which may carry grease, grit and metal chips, commonly produce surface soiling after many shop operations. Greases and other contaminants may also soil surfaces in food preparation and many other household and commercial environments. These contaminants may be corrosive by themselves, or may prevent the surface from maintaining corrosion resistance, therefore periodic removal is necessary. Initially, soap and water may be tried or a combination of soap and water with a solvent. This process, in its simplest form, consists of bringing liquid solvent into contact with the surface to be cleaned and allowing dissolution to take place; for example, washing a surface with trichloroethylene or similar liquid. Non-halogenated solvents, such as acetone, methyl alcohol, ethyl alcohol, methyl ethyl ketone, benzene, isopropyl alcohol, 6 toluene, mineral spirits, and turpentine work well. Many of these solvents are widely used as individual cleaners, but there are thousands of blended or compound cleaners on the market. Users are advised to contact suppliers of solvents for information on their applications on stainless steel.

TYPES OF CLEANERS AND METHODS

General Precautions – In selecting cleaning practices, consider the possibility of scratching and the potential for post-cleaning corrosion caused by incompletely removed cleaners. Scratching can be caused by cleaners that contain hard abrasives, or even by “grit” in wash water. This is usually not a problem on dull finishes, or those surfaces finished with a coarse polishing grit. The best preventative measure is to avoid using abrasive cleaners unless absolutely necessary. When abrasives are needed use a “soft abrasive” such as pumice, and always experiment first on an inconspicuous area. Many cleaners contain corrosive ingredients that require a thorough post-cleaning rinse with clean, warm water. However, thorough rinsing is recommended for all cleaning procedures.

Clean Water and Wipe – The simplest, safest, and least costly method that will adequately do the job is always the best method. Stainless steel surfaces thrive with frequent cleaning because there is no surface coating to wear off. A soft cloth and clean warm water should always be the first choice for mild stains and loose dirt and soils. A final rinse with clean water and a dry wipe will complete the process and eliminate the possibility of water stains.

Solvent Cleaning – Organic solvents can be used to remove fresh fingerprints, oils, and greases that have not had time to oxidize or decompose. The preferred solvent is one that is chlorine-free, such as acetone, methyl alcohol, or mineral spirits. There are many compounded or blended organic cleaners that are commercially available and optimize both clean-ability and safety attributes. Cleaning can be accomplished by wiping with a cloth that has been wet with a solvent, or by sophisticated vapor or spray methods. The wiping technique sometimes leaves a streaked surface; rinse with clean warm water and wipe dry with a towel.

Household Cleaners – Household cleaners fall into two categories: detergent (nonabrasive) and abrasive cleaners. Both are effective for mild dirt, stain, and soil deposits, as well as light oils such as fingerprints. The abrasive cleaners are more effective but introduce the possibility of scratching the surface. However, the degree of abrasiveness will vary greatly with the particular product – some brands will produce noticeable scratching on only the most highly polished surfaces. All of these cleaners vary widely with respect to their acidity and the amount of chlorine they contain. A neutral cleaner low in chlorine is preferred. The fact that the label states “for stainless steel” is no guarantee that the product is not abrasive, not acidic, or low in chlorine. The cleaning method generally employed with these cleaners is to apply them to the stainless surface and follow by cloth wiping, or to wipe directly with a soft cloth that has been wet with solvent. In all cases, the cleaned surface should be thoroughly rinsed with clean water and wiped dry with a soft cloth if water streaking is a concern.

Commercial Cleaners – Many commercial cleaners compounded from phosphates, synthetic detergents, and alkalis are available for the cleaning of severely soiled or stained stainless surfaces. When used with the appropriate cleaning method, these cleaners can safely provide effective cleaning. Manufacturers should be consulted and their recommendations followed whenever using cleaners of this kind. The general precautions stated above also pertain to these cleaners.

*NOTE: Use of proprietary names is intended only to indicate a type of cleaner and does not constitute an endorsement. Omission of any proprietary cleanser does not imply its inadequacy. All products should be used in strict accordance with instructions on package.

**NOTE: DO NOT mix chemicals without first consulting the MSDS Sheets, as mixing can produce fatally toxic gasses. If you do not have access to the MSDS Sheets, contact the manufacturer of the product. Scratch Repair

Scratch Repair

Depending on the severity of the scratch, it may be possible to completely remove it. Surface scratches can be repaired using the technique outlined below. It is good practice to clean and dry the scratched surface before sanding. Sand the scratch using 120-grit emery cloth or paper and firm pressure. Always sand in the direction of the grain. Avoid the natural tendency to sand in an arc, instead sand in a perfectly straight line. Sand until the scratch is gone. Polish using 3M scotchbrite pads – Very Fine Grade. Use the same motions as with sanding. Polish until the original finish is restored.

References

Much of the cleaning portion of this document was adapted from: Specialty Steel Industry of North America Care and Cleaning of Stainless Steel, Specialty Steel Industry of North America, 3050 K Street, N.W. Washington, D.C. 20007 (www.ssina.com)