Fingerprints and Stains
―Fingerprints and mild stains resulting from
normal use in consumer and architectural applications are the most
common surface contaminates. Fortunately, these fingerprints and
stains usually affect only appearance and seldom have an effect on
corrosion resistance. They are easy to remove by a variety of simple
cleaning methods. Fingerprints are probably the most troublesome
marks to remove from the surface of smooth polished or bright
finished stainless steel. Fortunately, they can be removed with a
glass cleaner or by gentle 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. There are several special
surface finishes where fingerprints present special problems:
polished No. 6 finishes, some abrasive blasted finishes, and light
electrochemical colors applied over satin or brushed finishes.
(Note:
There are several special finishes designed to withstand
fingerprints: embossed, swirl patterns, lined patterns, etc.)
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 contaminates may also soil surfaces in
food preparation and many other household and commercial situations.
These soils may be corrosive in themselves or may not allow the
surface to maintain passivity, and so periodic removal is a
necessity. Initially, soap or detergent and water may be tried or a
combination of detergent and water, plus a solvent. The removal of
oil and grease from stainless-steel parts by immersion in chemical
solvents is frequently used with cold-formed or machined parts that
are laden with lubricants. 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 or
stirring a batch of small parts in a container of solvent.
Non-halgenated solvents, such as acetone, methyl alcohol, ethyl
alcohol, methyl ethyl ketone, benzene, isopropyl alcohol, 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.
