For most stainless steel, warm soapy water is enough to lift away surface dirt and deposits. Follow the grain of the machined or polished surface, and avoid bleach, chloride-containing solutions and steel brushes or wool.
'Stainless' steel can still stain or corrode, just far less than lower alloyed or carbon steels. A steel is classified as stainless when it contains more than 10.5% chromium, which encourages a thin but highly adherent passive layer to form on the surface as soon as it is exposed to oxygen. Even so, dirt and deposits can build up, and localised pitting corrosion can cause discoloration.
A number of proprietary cleaning agents exist, but for most applications a few simple rules give an acceptable result:
- Use warm soapy water to lift away surface dirt and deposits.
- Never use bleach or chloride-containing solutions; if not fully removed, they greatly increase the risk of pitting corrosion.
- Do not use steel brushes or wool. Tiny embedded steel particles will quickly corrode and leave a rust mark that is very difficult to remove.
- Follow the grain of the machined or polished surface, which retains the original finish and cleans more effectively.