Stainless steel splashback stains

Tomato ketchup will clean stainless :)

You might run a magnet over it.If it attracts, then its the kind that will go rusty eventually as its an alloy with a ferrous metal of some kind. Brian

All stainless steel contains a high proportion of iron i.e. it is a ferrous metal. The different grades of stainless steel contain varying proportions of chromium and nickel to make it corrosin resistant. For instance yhe grade used for cutlery andgeneral houseware is known as

Malcolm

We had a dark room constructed at my former place of work, for developing electron microscope plates. It had a standard kitchen-quality stainless steel sink, probably obtained from a local builders merchant. Within a few weeks it was heavily corroded and rusty. They had to replace it with one made of a different grade of SS. I couldn't tell you which grade, but it didn't corrode.

"Cheap" stainless is often slightly magnetic and not as corrosion resistant as better grades such as 316. Dark-room chemicals are quite corrosive and it does not suprise me that "cheap" stainless was not up to the job.

Lightly rusted sinks/splashbacks etc will normally clean up OK with scotchbrite and/or weak acids. It's the vinegar in tomato ketchup which does the job.

I'll add ketchup to my grandson's meal next time he's round. His range improves with each visit!