I have spilled cooking liquid on the inside of the oven door while the oven was open. It seaped thru an opening and is now on the inside of the glass on the front of the oven door. How do I access the spillage to clean it? There are screws on the top (above the oven door handle) and bottom of the oven door. It appears that it will allow me to slide the glass out after unscrewing to clean it, but I'm concerned about refastening the screws. How can I clean the glass door? thanks!!