On the last 2 days of my 14-day MC last year, I did take Oxypowder (4 capsules with a glass of water with juice of half a lemon), just to see what I would get in my bowel movements. MC does loosen up the gunk on our intestinal walls and the Oxypowder helped me get rid of that gunk.
So, for myself, I would use Oxypowder again but only at the end of my MC (as an extra cleansing) but not during the main length of the MC.