I have just cleaned out all my nesting bowls no doubt alot of you will be doing the same prior to pairing , i have noticed even after soaking for 24hrs the bowls still seem pitted with calcium deposits obviously from the urine even after scrubbing , i soaked mine in Harpic power toilet cleaner and this helped remove the deposits just thought i'd post this to help others get there bowls as clean as i have , im very happy with the results