Debris is common. Just keep hydrated as hopefully should clear. Mostly it’s made up of scabbing in the bladder as the catheter retaining balloon irritates the bladder lining when in place. When I walked around for any length of time this was evident as I had pink urine on the catheter bag. Fully cleared around week 5 post op. If you have total block recommend consulting clinical staff.
clips can be made out of several materials depending on what the historian uses…. Titanium, polymer and fairly recently magnesium (which apparently dissolve after a year or so).