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Stainless Steel: Cleaning & Maintenance

How to Clean Stainless Steel?

Stainless steel is synonymous with long life and durability of appearance. Nevertheless, it is essential to clean their surfaces periodically, in order to remove dirt. Routine maintenance is performed as a preventive measure. The cleaning frequency depends on grade, surface finish, part geometry, and service environment.

Suggested cleaning procedures for common contaminations:

Contaminations	Cleaning Method
Fingerprints	Wash with soap, detergent, or solvent such as alcohol or acetone. Rinse well with cold water and wipe dry.
Oil & Grease	Wash with organic/hydrocarbon solvent (e.g. alcohol), then wash with soap or mild detergent and water. Rinse well with cold water and wipe dry. Soaking prior to cleaning in hot soapy water is recommended.
Paint	Wash with paint solvent using soft nylon brush, and then rinse with cold water and wipe dry.
Carbon Deposit or Baked-on	Soak in water. Use ammonia-based cleaning solution. Rinse well with cold water and wipe dry.
Heat discoloration	Use non-metallic scouring pad with non-abrasive substance (e.g. Brasso). Stain must be removed physically. Rub in the direction of the finish. Rinse well with cold water and wipe dry.
Label and sticker	Soak in hot soapy water. Take the label off and remove glue with methylated spirits or benzene. Followed by washing with soap or detergent and water. Rinse thoroughly with hot water. Wipe dry with soft clean cloth.
Water Marks-Lime Scale	Heavy scale can be loosened by soaking in 25% vinegar solution or 15% nitric acid. Rinse well. Followed by washing with soap or detergent and water. Rinse thoroughly with hot water. Wipe dry with soft clean cloth.
Tannin-Tea and Coffee	Wash with washing soda (sodium bicarbonate) in hot water. Followed by washing with soap or detergent and water. Rinse thoroughly with hot water. Wipe dry with soft clean cloth.
Rust stains	Soak parts in 9:1 warm water to nitric acid solution for up to 1 hour. Wash thoroughly with water. Or Wet the surface with oxalic acid solution and leave it for approximately 20 minutes. Rinse well with cold water and wipe dry. Or Mechanical de-scaling may be needed in case of hard-to-remove rust stain.
Use precaution and appropriate equipment when handling acid. Please contact an expert if there is any doubt.

Recommended Cleaning Frequency (Time/Year):

Grade	Atmospheric Environment
	Rural		Urban		Industrial		Marine
	Normal	Severe	Normal	Severe	Normal	Severe	Normal	Severe
430 (TNX SC17)	0	0	x	x	x	x	x	x
304 (TNX S,D,DDQ189)	0	0	1	2	2	x	x	x
316 (TNX SM 1710)	0	0	1	1	1	2	2	x

Note
Rural:	Area where there is a minimal amount of chemical pollutants. Moisture, oxygen, and carbon are the main pollutant. Ex. Ayudhya
Urban:	Area exposed to typical urban contaminants of SOX and NOX emitted by motor vehicles. Ex. Bangkok
Marine:	Area contaminated with sea salt (chloride), which is carried by wind and deposited on materials. Ex. Phuket
X:	Not recommended for application in this environment.

Dos	Don'ts
When cleaning is not performed routinely, stain and dust should be removed as soon as it is observed.	Don’t coat stainless steels with waxy or oily substance, it will cause dirt and stains to cling more easily to the surface and make them more difficult to remove.
Always start with the mildest cleaning products and methods on a small area to evaluate the effect on the surface finish.	Don’t use cleaning products containing chlorides and halides (e.g. Bromine, Iodine, and Fluorine).
Use warm water to help removing greasy and oily contaminants.	Don’t use disinfectant to clean stainless steels parts and components.
Always rinse with clean water as the final cleaning step, followed by wiping dry with soft cloth or paper towel.	Don’t use hydrochloric acid (HCI) for cleaning. This will lead to pitting and stress corrosion cracking (SCC).
Adopt appropriate protection and precaution when using acid to clean stainless steel.	Don’t use suspect products.
Always wash stainless steel utensils as soon as the food preparation is finished.	Don’t use ‘Silver’ cleaner.
Avoid ferrous contamination from cleaning equipment made of iron or used to clean plain carbon steel parts.	Don’t use excessive amount of soap and detergent for cleaning. It will leave ‘cloudy’ film on the surface.
In the event of uncertainty or difficult cases, please contact an expert for further cleaning instruction.	Don’t clean any passivity part in a single step. Cleaning should be performed prior to the passivation treatment.