nangs can be like a massive excursion out of the normal space-time-continum, pretty epic.... Have given the mosa nangs a pretty decent test, little bit of black residue in the machine after some decent use (~ 150 perhaps?), but less oily stuff than the whip-its...meh, tis all good.
Really? I find the whip-its leave absolutely zero residue. ie. the blue boxes with smiling kids on it.
Isi's do have a tiny amount of residue but not enough to be significant.
Mosa bulbs are disgusting. Can actually feel the residue hit the back of your throat after putting a few boxes through the machine. Never. Again.
Steer clear.