Is the glass in your oven door grease splattered? The old standby cleaner that's the cheapest and makes grungy things sparkle, ammonia, is poured into your dishcloth and wiped onto the glass to wet it well. Then use a paint scraper (the kind that uses a razor blade) to scrape away the grease spots. Keep the area wet with the ammonia while scraping. Rinse well and it's sparkling clean.