Stainless steel can be a challenge to clean and keep in good condition. Many people abuse stainless steel by using the wrong chemicals.
Stainless steel is maid “stainless” via the passivation process where the free iron was removed from the surface of the metal using an acid solution to prevent rust.
The wrong cleaning chemicals can ruin this “passivation protection” in seconds.
Don’t get bleach, ammonia, or any brutally strong acid (such as HCL or muratic acid) near stainless steel.
While there are specific acids we mention later that work great on stainless steel there are some that will destroy it by even being near enough to it to ruin it with black streaks from fumes alone.
The best way to maintain stainless steel is with an oil based stainless steel cleaner that contains citric acid. Citric acid acts as an indirect passivator as it starts to react with oxygen after a while further protecting the surface from oxidation.
Sometimes you will need to aggressively treat stainless steel that is oxidized and/or has calcium/lime buildup such as a sink or water fountain. The best method is to use a safe acid such as phosphoric acid (QA Foamy is a product example) or oxalic acid (Barkeeper Friend) to remove this and then, after, clean off with a stainless steel spray.
Stainless steel will keep looking great as long as you follow the basics: