What I do to cleanse my system is this:

buy a bottle of generic fiber pills (the generic equivalent of Metamucil caplets)

take literally 40-50 of them before bed

Have a satisfying dump the next morning

do it again that afternoon (you've basically crammed the whole bottle in two days)

big time poop-o.... BIG time that night or the next morning. One time I did this and a fleshy, lined tube came out of me. I mean, seriously. It looked like a pork sausage with a clear, almost see through skin, filled with chunks of ... well, crap. It was about 12 inches long and just massive. I felt so clean. It's like a mucoid lining or something, I'm no doctor, but man it works.