Can glass go in the microwave? It is very common that we feel the need to put glass in the microwave. Not all glassware is microwave-safe. Check the bottom of the container to look for a microwave-safe symbols, otherwise, simply run a test by filling up the glass with water and microwave on high heat for one minute. If the glass is heat resistant, the water will become hot and the glass will remain cold. However, if the glass becomes hot and the water inside is cold, then the glassware is not capable of microwave use. Unsafe glassware may cause an explosion in the microwave. Decorative cups are generally not safe for microwave, but glass cookware without silver or gold rims are microwave safe.