An apparatus for removing excess of a sterilization agent from a web of carton-based packaging material is presented. The web comprises a number of consecutively arranged sections arranged to be formed into packages, wherein each section of the web comprises an opening device attached thereto, wherein at least a subset of the sections comprises a positioning element. The apparatus comprises a positioning element reader arranged to determine a position of the positioning element comprised in or on the web, a control unit configured to estimate a position of the opening device based on the position of the positioning element, and an air pulse device arranged to provide an air pulse, wherein the control unit is further configured to adjust the air pulse device based on the position of the opening device, and the air pulse is provided onto an opening device area of the web such that sterilization agent is removed from the opening device.