Hi Simone, this link may be of help to you...
I've used different methods. A product like CLR works. Try a little WD40 if you have it. Good luck and stay safe!
I use Young Living's Thieves cleaner
Hi Simone: I use a product from the Dollar Tree called LA's Totally Awesome Rust Lime and Calcium All-Purpose Cleaner. And, it only costs a dollar :) I spray it on and leave it maybe a 1/2 hour and then rinse it off. Depending on how bad your rust is, you may have to leave it on longer. Good luck
I found this:
''You may not like the taste of lemon but you’ll love its cleaning properties when it comes to removing rust. You can use lemon juice as a cleaner in a couple of different ways. For a simple solution just pour it straight onto the area of tile that is affected and leave it in place for five minutes; do not allow the juice to dry. When the five minutes is over grab an old toothbrush and scrub at the stain. If you’re still having problems removing the stain add some more lemon juice to the area, together with some salt, and leave it to rest for three hours before scrubbing the solution off with the toothbrush, using warm water.
The other method of using lemon to remove rust stains from ceramic tiles involves mixing it with baking soda and applying the resulting paste to the stain. This should be left in place for half an hour before it is scrubbed off with a sponge or soft brush.''
You could try some CLR for this. Test a small spot first.
Hello Simone, here are a few things for you to try, hope they help!