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.
Flush the toilet two or three times until the water in the bowl is clear. After the last flush, wait for the tank to fill up with water and for the fill valve to turn off. Add six drops of red food coloring to the water in the tank. Check the water in the bowl after 30 minutes.