We understand that it’s unsightly, but it's a bit of a tricky situation. Some oven doors can be opened with a few tools so you can get at the glass and clean it with oven cleaner like the rest of your appliance. But be careful not to apply the oven cleaner to any rubber seals around the oven’s door. If you’re unable to open up the door to clean the glass, you might have to get used to the grease stain. Hang a cute kitchen towel over the door handle to mask the stain.