For access to the piston cork the grip section must first be unscrewed; it is connected to the barrel via a resin-sealed thread; this resin melts on careful warming faster than the plastic of the barrel, but on too much heat or force, breakage damage is unavoidable. For loosening, a small pipe wrench without sharp teeth with leather underneath is recommended, plus fingertip sensitivity. The feed with nib is either disassembled at the section or driven out from behind through the barrel with a supporting block (small vice); the section must absolutely be supported, otherwise it breaks. Warming with a hairdryer is helpful. Anyone failing repeatedly should leave the repair to experienced specialists, since the follow-up costs of damaged nibs, feeds and grip sections far exceed the original effort.