A method for clearing outputs of a mail sorting machine concurrently with a current sorting cycle of a mail sorting process is disclosed. At each sorting cycle, each output of the sorting machine is assigned a number of respective delivery locations of the mail items. An indication of the time intervals when the outputs are available or unavailable, is represented by a matrix. Each element in the matrix is assigned a delivery location; and the column and row of each element represents the outputs occupied, by the mail items bearing the delivery location assigned to the box, at the end of the current sorting cycle and the logically preceding sorting cycle respectively. The method provides for defining non-addressable elements to which delivery locations cannot be assigned, so that the outputs may be cleared by a clearing resource at that time.