Rectal delivery is recommended by Chris Hyslop as "the" best method of quickly building up CS in bloodstream.
I have been doing this for the past few weeks. Inserting an ounce every hour for several hours. I use 2 ounces of CS I purchased from Utopia-Silver & then 3 ounces of CS created by high voltage & 3 ounces of CS created by low voltage. I also do a couple of ounces throughout the day held in the mouth. I haven't noticed anything (good or bad).
I would think that using CS as a flushing method would be wasteful.
Make sure you take probiotics, there is a good chance of the possibility of killing good bacteria along with the bad.