I beleive you answered your own question number 12546!
"'My speculation is that it is the extremely acidic waste causing this that my body now has the ability to extricate-""
I do much more cayenne then a 1/2 a teaspoon of cayenne, sometimes as much as a whole tablesppon at a time without this effect!
Plus I also experienced a burning sensation when I first started the cleanses a long time ago!
Once your body has built up its alkalines supplies and released the toxic acidic waste this will cease to accur!