The reason why you should put toothpaste in the toilet tank is because toothpaste is antibacterial so it eliminates germs and bacteria.
The germs and bacteria are what gives your toilet a bad smell.
The toothpaste in the toilet tank also gives the toilet a fresh smell and minty smell that leaves the toilet and your bathroom fragrant and smelling good.
If you use toothpaste that contains baking soda and peroxide in your toilet tank, in theory, it should help improve the overall smell, stain removal, and disinfection of the toilet and toilet tank.
However, the people who use toothpaste to clean their toilets usually do so by scrubbing with it manually.
You can also use some baking soda and vinegar to clean your toilet bowl and keep it smelling fresh.
If you want to keep the tank cleaner for longer, you can also go back in with the vinegar, adding a cup or two to the tank once a month, letting it soak, and flushing the toilet the next morning.
You can also put a bar of soap in your toilet tank and every time you flush, the soapy water will clean the toilet's internal plumbing and wash out the bowl.
And soapy water is actually quite effective at removing mold from hard surfaces, like the inside of your toilet tank.