The REASON that the colon walls don't look dirty, with encrusted fecal matter attached, is that it simply doesn't happen.
Perhaps in very rare cases, encrusted buildups have occurred, but with so rare a frequency that it's most probably not happening in you.
That's not to say that some of the horrific pictures we have seen over the years didn't happen. But, I suggest that it would be quite helpful if those pictures had a dateline attached to them. I suspect that the pictures are very old, and represent a very rare condition. I wish they weren't used to try and frighten us, because I believe they represent a red herring in colon treatment.
See? According to my research, it's NOT the de-pooping which has the beneficial effect in healing or "improving" mood, digestion, and/or overall health. That's largely a misnomer, and it's why the medical community can so easily and steadfastly object to treatments like enemas and colonic irrigations. The "science" does NOT support detoxification through the removal of feces.
What IS most likely happening in "effective" treatments -- is a body chemistry change, from the addition of large quantities of water into the colon over about a 45-minute period. This water comes to us with a pH of about 7.3, courtesy of the public safety and water engineers. What actually sets the limit on the duration OF a colonic irrigation is when the patient's bladder gets full from the absorbed liquid taken up BY the colon, which IS, of course, the colon's natural function.
The same thing happens in an enema, and it can be augmented, usually to the patient's benefit, by the addition of ordinary, kitchen-cooking-quality, baking soda, to the enema or colonic irrigation water. This is because ordinary baking soda has a pH, in the box, of about 8.0. Injecting so-called, high-pH solutions such as this into the colon causes the body to "take up" pH, such as it were, probably by relinquishing excess H+ ions in the body TO the liquid in the colon. Depleting H+ ions, which ARE the source of excess acidity in the body "restores," or "re-normalizes" body pH to the God-given level of about 7.35 to 7.45, call it 7.4, for purposes of discussion. (Please, everyone, try to remember that pH, by definition, IS the measurement OF the "negative logarithm" of the concentration of H+ ions in an aqueous [water-based] solution). But, we digress.
The REASON all this is important is that re-normalizing the body's excess acidity re-normalizes the pH of the blood, which allows for significantly greater oxygen saturation capacity OF the blood, which helps the brain, and all tissues, do THEIR work better. On top of that, THE REASON why most colonic patients report an "elevated" mood or feeling of contentment in association with, or after, a colonic irrigation or enema is that re-normalizing the blood / body pH also allows the brain receptors which take up and process the body's naturally-occurring endorphins, serotonin, and serotonin-like chemicals to be processed/absorbed/accepted BY the brain receptors looking for those chemicals in the blood.
That's why colonic therapy or even simple, water-based, home enemas (with baking soda in the enema solution) can be, and have been, successfully used to treat ADD and ADHD in children, and / or Depression in adults. The patients' bodies simply absorb and process MORE of the endorphins, etc., in a less-acidic, more-natural pH enviroment of 7.4 than they do in the presence of a lowered pH.
It's also the reason why cancer, Multiple Sclerosis, Lupus (SLE, included), and other, so-called, "dread diseases" also typically respond well to what is now called "high-pH" therapy. Contrary to popular belief, these diseases are NOT untreatable, and many of them respond quite favorably to "only" augmenting the pH by supplementation with baking soda solution injected into the colon in the form of an enema, or in a colonic irrigation -- IF you can get your therapist to even add baking soda to your colonic.
What's happening when you do that -- is -- when your body pH is lowered, meaning you have excess acidity, your body's natural "immune system" begins to lose ITS functionality in DIRECT proportion to how much your pH has been lowered. The good news is that AS YOU RE-NORMALIZE body pH, your immune system functionality also returns fairly linearly TO most of its efficacy and functionality. Liberating your immuns system to do its job causes (or "allows") your body to heal of its various ills.
No medical provider can "heal" a patient. Of course, if you feel you need medical care, by all means, see a medically-licensed health-care practitioner. But, if all you are looking for is for your body to heal, from many of society's current health crises, it may be your best bet to try re-normalizing your pH before you try anything much more radical. None of the above is an attempt to practice medicine, or to treat illness or disease, because if you have an illness or disease, you probably ought to seek out the services of a physician. On the other hand, most practitioners primarily try to keep a patient alive, until the patient's own body can heal itself. All the drugs and proprietary pharmaceuticals tend to be oriented in the direction of keeping patients' alive while their body "does the work," so to speak.
ALL of the above is for the purpose of advocating seeking "Mother Nature's" own healing, by allowing the body to re-vitalize the tremendous immune system with which most of us were born.
Any serious debate on any of the points made is welcome. Please don't bother yourself to make mere critical commentary from the sidelines. Too many cases of successful healing have been observed -- to accept unfounded, or irrational prejudice of what is essentially THE most-natural method.
Interestingly, almost accidentally -- all of the most modern, medically-based research IS focused, in one way or another, on exactly the same thing as the above, i.e., finding ways to re-normalize body pH by reducing the acid-burden incurred by most modern Americans. Without knowing they are seeking "The Holy Grail," most research attempts to change pH by changing / reducing acidity. All that is suggested is thinking about manipulating pH, directly, and letting nature take its course. Anyone with any serious maladies may feel free to enter this discussion. If you post your contact information, it's possible for me to contact you, directly.
Thank you for your considered opinion of an important healing topic.