The small intestine is called small because the diameter or the width of the tube is much less than the large intestine. The parts of the small intestine include the duodenum, jejunum and the ileum. The duodenum is a segment of intestine between the stomach and the jejunum that is very active in digestion where many different enzymes mix from the stomach, liver, gallbladder and pancreas. The small intestine is the location in the body where the majority of the nutrients from ingested food ...
CLR is a common household cleaner that is designed to clean the heavy duty stains of rust, calcium, and lime. Usually these stains are caused by water build up and the constant drip of minerals in the water.
Sometimes those toilet stains are from bad water and should be dealt with as such. Regular bowl cleaners won't work on mineral deposits. I wrote an email to the CLR people to suggest they make a little disc to put into the flush tank to clean as you flush. I'll let you know what their response is.