A method of removing unwanted edge copper from an edge region of a wafer is provided. An annular fluid filled tuning chamber is disposed adjacent the orifice track and separated therefrom by a flexible membrane. The securing members are detachably and selectively fastened in opposite vertical supports to support the corresponding shelves at the desired positions, whereby distances between adjacent shelves are adjustable. The ice making unit may dispense ice on call or on cash demand. The at least one token-based rule may condition access to the resource upon a second token.