A method and apparatus for forming vents (13) in glass sheets (10). The method includes repetitively performing the steps of: (I) bringing a score head (21) and a platen (31) into contact with, respectively, the front (11) and rear (12) major surfaces of the glass sheet (10), (II) moving the score head (21) across the front major surface (11) along a predetermined path to form a vent (13), and (III) withdrawing the score head (21) and the platen (31) from the front (11) and rear (12) major surfaces, wherein: (i) the thickness (δ) of the glass sheet is less than or equal to 500 microns, and (ii) for each repetition of steps (I) through (III), the platen (31) is cleaned after step (III) and before step (I) to remove glass chips which if left on the platen (31) could cause the score head (21) to penetrate through the thickness δ.