or similar object particularly in the press or dryer section of a paper machine or similar equipment the orifice slot is subjected to treatment from inside the blow box by means of one or more mechanical cleaning elements and or a cleaning jet the invention also concerns an apparatus suited for implementing said method application_number US 14540893 A description with reference to fig1 a blow box 1 employed in the press or dryer section of a paper machine or similar equipment is shown in partially sectional side view the blow box 1 has two orifice slots 2 3 which are advantageously aligned perpendicular to the web machine direction extending advantageously over the entire width of the web and a manifold for routing the blowing air into the slots the orifice slot 2 is provided with a mechanical cleaning element 4 which is moved over the longitudinal direction of the orifice slot 2 by means of a drive machinery 5 6 7 the drive machinery is comprised of one or more advantageously three drive wheels for instance chain sprockets 6 and a drive chain 5 or similar means routed through the drive wheel set the cleaning element 4 is arranged movable along with the drive chain 5 or equivalent means as shown in fig3 a drive actuator such as an electric motor 7 is arranged to rotate the drive wheels 6 via e g a shaft the motor can also be of a reversible type thus permitting a reciprocating movement of the cleaning element.