Indeed, some of the most controversial elements being overturned or prohibited by the Every Student Succeeds Act were implemented not under No Child Left Behind but through the waiver system. It was through the waivers (and the Race to the Top grant program) that the Obama administration mandated test-score-based teacher evaluations.
Vinegar, bleach and borax powder are some examples. Bleach -- If you want to use something stronger than vinegar, then use bleach. Bleach is best used when the rings and stains are already too tough. Pour half a cup of powder into the toilet bowl. Leave it that way for a few hours before you flush the bleach away.
, I have owned a residential cleaning and home management business for 20 years. Lime-Away toilet bowl cleaner (not spray cleaner, which is a different product) is EXCELLENT at getting out really tough stains in toilets. I have been successful cleaning toilets brown with water stains decades old with this product. It may take a few uses, allowing it to sit on the toilet bowl for several minutes at a time, but it will get it clean.