ᐅ Rust stains on tiles – is there anything that can be done?

Hello, I accidentally caused some damage to the tiles in a rental property. Where the metal shelves were placed, there are rust stains. I have already treated them with a special spray. The reaction was quite impressive, but the result is disappointing.

Does anyone have any advice for me?

What have you already tried?
Common tips you find are citric acid / vitamin C powder (due to ascorbic acid) or concentrated vinegar. Letting it sit longer, repeating the application (if it improved but didn’t completely go away), or warming the surface is also said to help.
I found a video on YT where someone uses Mellerud spray and heats the tiles with a hairdryer beforehand.

By the way, you should be careful not to get anything into the grout if possible.

Edit: Is that even a regular tile? From the look of it, it seems like granite or something similar?

What kind of material is this? Natural stone? It looks a bit like what we had in the stairwell of our rental apartment. The surface was very sensitive to acids. So I would be very careful with lemon juice and vinegar.

I also used this Mellerud. As I said, it didn’t exactly impress me. The tiles are probably granite. I’m not an expert in that area.
I will also try using a hairdryer...

Yes, if the material is natural stone, you need to be careful with acids. However, there are special cleaners designed for removing rust from granite, natural stone, and similar materials.

There is an "HMK R777" rust converter for hard stone, but it is only suitable for acid-resistant surfaces. There is also an HMK R179 rust stain remover for soft stone, which is intended for acid-sensitive stones. You might want to look for these products. They are not exactly cheap, around 20€ per bottle.

Vinegar has proven effective on our terrace slabs/tiles. However, pay attention to the underlying surface. Lithofin offers specialized cleaners for many applications; it might be worth checking there.