The ring around the bathtub is caused by soap scum an dirt. The ring can be washed off using bathroom cleaner.
Dirt
Your bathtub. Go clean it.
Fluorine
stratum corneum
bathtub ring
The color of the ring that the cat leaves in the bathtub in "The Cat in the Hat Comes Back" is pink.
PINK
This might refer to the dirty ring left around a bathtub when someone soaks in a bathtub with soapy bubbles then empties the water. The dirty soap clings to the the sides of the bathtub leaving a ring mark of residue where the high water level was.
PINK
The ring of fire is a group of volcano's surrounding the pacific. Volcano's are formed by 2 continental plates colliding and a magma chamber was under neath. It is named ring of fire because it is a ring of volcano's.
PINK