Try a product called 'Scouring Stick'. It's pumice and is sold in Walmart.

Hi there, this is a DIY natural solution. I've tried it with success. https://www.hometalk.com/16727398/removing-nasty-toilet-stains

Removing Nasty Toilet Stains

Citric acid can help the stains go away, it’s a mild acid, won’t hurt thecomode

I also use a pumice stone. It doesn't harm the finish at all but works great

pour a can of Coke and leave it overnight

Baking Soda

This works well for removing stains from toilets or sinks: https://amzn.to/2wGe1Nr

Hope this Helps! Jeremy - https://pahjodesigns.com

Coke the soft drink will remove these stains. Seriously. Turn water off to the tank, flush toilet, then fill to the brim with Coke. Let it soak and it will take those stains off

check that pin https://www.pinterest.com/pin/117867715234959603/

I use Young Living's Thieves cleaner to clean our toilets

WD 40, MY HUSBAND TOLD ME THIS TRICK. SPRAY IT ON AND LET IT SIT FOR A FEW MINUTES AND IT WILL TAKE IT OFF. ALSO, BAKING SODA AND VINAGER.

I agree with Annie, I have used the Coke technique and it works like a charm!

Faye

See if this video helps you out.

https://www.youtube.com/watch?v=vyTmZjPbkOM