C.P is a bio-active (live aerobic bacteria) product, same as K.O. Although the bacteria exhaust themselves after 24 hours, it can remain in the plumbing indefinitely without harm.
Vinegar should never be left to sit in the bowl because it's destructive to soft rubber --joker valves. A weekly cupful--MAYBE 2, but no more--flushed all the way to the tank, then flushed out with clean fresh water after 45-60 minutes will PREVENT mineral buildup in hoses. It CAN clean out a buildup, but it's too labor intensive--must be replaced hourly (the instruction that all the people who insist it won't work always miss),making muriatic acid a much better choice. Muriatic acid should also be rinsed out with clean fresh water after 45-60 minutes.
--Peggie