GuideStreak-free glass with microfibreThe two-cloth method: a flat-weave cloth to clean, a dry one to finish, and a cleaner that evaporates before it can streak.DifficultyEasyTime15 minutes
HomemadeStreak-free glass cleanerEqual parts vinegar and water. The most reliable residue-free mix there is, and the reason it works is the second, dry cloth.DifficultyEasy