A Magic Eraser will remove some toilet bowl rings as long as the toilet bowl ring is not really stubborn.
I've removed a toilet bowl ring with a Magic Eraser and it worked great it just requires some scrubbing in the toilet.
You could tape the Magic Eraser on a stick or use gloves and just use your hands to hold the Magic Eraser to clean the toilet bowl and remove the toilet bowl ring.
A good way to get rid of a toilet bowl ring is to use some Borax powder and vinegar.
To get rid of toilet bowl ring using Borax and Vinegar just follow these directions below.
Take some borax and sprinkle 1/4 cup of the borax into the toilet bowl and swish it around with a toilet brush.
Next add 1 cup of vinegar to the toilet bowl and then swish it around again, and let the mixture sit in the bowl for about 20 minutes.
After 20 minutes have passed you can then finish it by scrubbing the bowl with a toilet brush to remove the stains.
Then flush the toilet rinse borax and vinegar and toilet bowl ring stain off the toilet bowl.
You can also use CLR in the toilet to help remove toilet bowl rings as well as calcium deposits and other stains.
CLR is safe to use in porcelain toilets and in toilet bowls and toilet tanks as well.