On my first flush (I've done 6 now and will do another tomorrow night) I caught my morning eliminations in a collander. On one of the discharges I got what I am certain was sludge. If looked like a pile of green grits. The pile was about 3" in diameter and 1/2" high. I know I had sludge in my gallbladder from a Heida Scan that had been performed 6 months earlier.