How do I get rid of stubborn stain ring in toilet bowl?

Try using toilet cleaners from store ormay be Cola left in overnight or pumice stone.

you can use a wet pumice stone or an acidic cleaner like vinegar or CLR

Hello Robert: Are they mineral (hard water) stains, rust, or something else? Here are a couple sites that may help:

6 Types of Toilet Bowl Stains and How to Remove Each One – RusticWise

Cleaning Pros Explain the Best Way to Remove Hard Water Stains

Power of Hydrogen Peroxide for Toilet Cleaning: A Complete Guide

How to Remove Rust Stains from Toilets? (6 Easy Ways)

How to Clean Toilet Stains: 4 Top-Notch Methods

Good luck

Hi Robert, hope this helps you. To remove stubborn mineral rings, limescale, or rust stains from a toilet, use acidic solutions that break down hard water buildup rather than basic scrubbing

Method 1: Vinegar and Paper Towel Soak (Best for Mineral Rings & Limescale)

1. Lower the Water Level: Turn off the water supply valve behind the toilet and flush once, or use a plunger or cup to scoop out most of the water so the acid isn’t diluted.
2. Apply Acid to Vertical Stains: Line the stained area or hard water ring with toilet paper or paper towels.
3. Saturate with Vinegar: Soak the paper towels thoroughly with undiluted white vinegar or cleaning vinegar so they stick directly to the porcelain.
4. Let It Dwell: Leave the vinegar-soaked paper in place for several hours or overnight.
5. Scrub and Flush: Remove the paper towels, scrub the area with a stiff nylon brush or toilet brush, add a bit of baking soda for extra grit if needed, and flush.

Method 2: Citric Acid Powder (Best for Heavy Brown Limescale)

1. Empty the Bowl: Turn off the water and flush to lower or empty the water level.
2. Add Citric Acid: Pour about 3 tablespoons of citric acid powder and some warm water directly into the bowl.
3. Soak and Dissolve: Let the solution sit undisturbed for 7 to 8 hours or overnight as the acid forms chelates to lift the metal and mineral ions.
4. Scrub Away: Brush the softened scale away and flush. For details on managing mineral buildup,

Method 3: Commercial Acidic Cleaners or Abrasives

1. Cling Bleach Gel or Heavy-Duty Cleansers: Apply a cling gel or abrasive cleaner like Bar Keeper's Friend, Comet, or Ajax, and let it sit for at least 10 minutes to break down embedded residue before scrubbing.
2. Pumice Stone: For heavy, calcified rings that refuse to dissolve, gently rub a wet pumice stone or fine steel wool (like an SOS pad) across the porcelain, keeping both the stone and the surface wet to prevent scratches