The oven itself and the racks on which trays are placed are kashered by cleaning them and running the oven on its hottest setting for half an hour.
Baking trays are not kashered because they absorbed through fire, and kashering them requires libun at a temperature of 400oC, which will likely cause them serious damage (above, 10:5 and 9). One should therefore buy special baking trays for Pesaḥ, while the ḥametz trays should be cleaned and put away like all other ḥametz utensils. Instead of special Pesaḥ trays, one may use disposable trays.
Baking trays in which ḥametz is baked cannot be kashered because custom follows the stringent view (above, 10:5) that requires a temperature or 350-400oC to kasher them by means of libun, which will damage them. However, one who wants to rely on the lenient view, that even libun only requires heating up to the temperature at which the baking took place, may kasher the baking trays in the oven, as explained above (10:5).