One embodiment of the invention relates to a method for conditioning resistive memory cells of a memory array with a number of reliable resistance ranges, where each reliable resistance range corresponds to a different data state. The carriage is slidably supported on an upright rail together with, and moveable independently of an actuating member, to which a handle is fixed, and a support member urged by a spring to an uppermost position. The closure provides for the dispensing of product in a clean and controlled manner without mess. Manual disengagement is required to unlock the lifting dogs and release the spearhead.