Clogging of venting slots in injection molds is a common maintenance problem related to the degradation of the resin and the accumulation of corrosive residues on cavity walls. In this work, the effect of laser-induced periodic surface structures on the self-cleaning properties of venting slots was investigated. The degradation of PET over different surfaces was characterized using a specifically design experimental setup. The results indicate that the use of regular nano-structures aligned along the flow direction minimizes the deposition of gaseous residues on the venting slots.