“How do you clean badly stained dentures?”

I would take them to your dentist. Sometimes it can void the warranty if you damage the denture experimenting.
My hygienist cleans my denture patients dentures. Sometimes a multi step process.
Ultrasonic cleaner like a jeweler uses… a mechanical ultrasonic scaler and also soaking in Polident etc. Also manually with a toothbrush cleaning.
I’d have to see it.
Dr. J

If your dentures are stained from years of smoking or coffee or tea use, you may ask you dentist if they can professionally clean them ultrasonically with a special solution designed to remove stains and tartar. If that doesn't work well, it may mean that the stains have been absorbed into the acrylic of the denture base and teeth and simply cannot be removed. Then the only option to get rid of the stains would be to replace them. Whatever you do, do not clean or soak them in bleach. Household bleach may remove stains, but it can also take all the pink color out of the denture base, leaving it white and totally unnatural.

You also have to ask yourself, "What caused the stain?" If something is doing that to your dentures, what is it doing to your body?

Dr. Conrad

Take it to your dentist and have them clean it in the denture cleaner solution in their ultrasonic cleaner. All dentists usually have that.

Soak overnight in straight, undiluted white vinegar. The next morning, scrub well with Dawn dish washing liquid using a stiffer brush made for cleaning dentures. Might need to use a wood style toothpick for the spaces between the teeth and the artificial gumline. Rinse well, splash with favorite mouthwash.