Glass-topped stovetop (range) (Kashering) Status: May be kashered by cleaning it, not using it for 24 hours, and then leaving all four burners on the highest setting for 30 minutes. When kashering for Passover, cover the area between the burners (after kashering) and do not put pots or food directly onto that part of the glass. An alternative for a glass stovetop is to not kasher it at all, and instead place all pots onto metal discs so that the pots have no contact with the stovetop.