How to remove flash rust from a stainless steel door handle?

Hello, the stainless steel handle of my side entrance door is rusting.
Does anyone have any tips on how to care for it?
Thank you

We have the same problem. However, we have not taken any action against it yet, so I would also be grateful for tips.

But I have also read tips on the internet where lemon juice (concentrate) and cola were used.

What material is the gray area, where the handle is attached, made of? Is the handle placed on there or continuous?
The corrosion can have several causes. It looks like crevice corrosion, i.e., the design with the gap causes the protective oxide layer not to form there due to insufficient oxygen, so that even stainless steels can corrode. Humidity in the air is then sufficient.
If the pipe rests on the gray area, it could also be that the material was contaminated during processing, e.g., by working with tools that have already seen rusting steels.

In any case, the handle should be dismantled and the corrosion removed by grinding/polishing and then the spots should be passivated if possible. Either with stainless steel pickling paste (expensive and toxic) or with cola/lemon juice (no joke).
Afterwards, keep the area as clean as possible. If it was only contamination, it should remain rust-free in the future. If it is actually crevice corrosion, then occasionally treat the area sparingly with a care oil to deprive the corrosion process of the necessary medium (moisture).

I do everything with baking soda. You can buy it in a 5 KG bucket :)

Sidol and done.

Use [Flugrostentferner] for the car. Although most of them stink, after one or two rounds it’s gone. Then rinse well. Also unproblematic on painted parts. Afterwards either stainless steel care from [Würth] or WD40.