Kashering baking trays

We have two ovens, one dairy and one meat, and they have identical metal trays. We got confused, which one is which, and now it’s impossible to distinguish which the meat tray and the dairy tray. Is it permitted ab initio to choose one tray and activate the oven on maximum heat with the tray inside, and thus allow it for further use?

Dear …!
Yes, you are allowed to do this, and the tray will be permitted for use. (Even though ab initio it’s forbidden to transfer utensils from meat to dairy and vice versa by kashering them, in this case, since they got mixed up, it’s permitted to kasher them.)