Hello, it's easy, you take out the hose that is inserted into the butterfly body, take out the butterfly screws and loosen the step by step, (Never move or touch it) Remove the old seal (You must buy a new one) And with the spray of CLEAN LEATHERS of butterfly or Naphtha with a blowtorch, clean the charcoal, (Without touching anything, it will only fall, at most with a small brush N7 You do it, but avoid it, use the fall or inclination having the piece in hand) I take this, you put it back with the same or more care and ready.