Nothing makes a kitchen look grungier than a glass oven door that is coated with years' worth of baked-on grease. Thankfully, it only takes some elbow grease to clean the inside and outside of the door. If you want to go all the way, you also can take the door apart and clean the insides of the panes of glass.
Use a paper towel to apply a coat of rubbing alcohol to the oven window, and let it sit a few minutes. Scrape with a razor blade and watch layers of grease give way to clear glass. It takes a little pressure to cut through the grime, so you may want to invest in a blade holder to help you hold on tighter.
If you don't have rubbing alcohol on hand, substitute Cameo cleaner, Windex or dishwashing detergent. You might have to work a little harder with the detergent, but the grease will still come off.
To clean inside the glass panels, carefully remove the oven door and take it apart. Clean the inside of the glass with alcohol and a razor blade. When you replace the door, make sure the seals are in place. If you don't feel comfortable handling the door, ask a technician to clean the inside the next time you get your oven serviced.
To avoid grease build-up on the glass door, wipe your oven clean before you use it for extended periods.