In the user manuals for gas fireplaces, Majestic recommends applying a non-abrasive mild cleaner, then wiping the cleaner away with a soft, damp cloth. For wood-burning fireplaces, the company recommends using a commercial oven cleaner first, then removing any residues with a glass cleaner or a water and soap solution.
Before the cleaning, it's important to make sure the fireplace is turned off and the glass isn't hot. The way to safely remove the glass for cleaning can be specific for the type of fireplace. All cleaning solutions used need to be nontoxic, noncorrosive, and non-abrasive. An alternative for a commercial glass cleaner is vinegar, and ashes on a damp cloth can serve instead of an oven cleaner.