Our opal glass cups are built for daily drink service. They can be used for coffee, tea, milk and other hot drinks. The smooth surface is non-porous. It does not hold coffee stains or tea marks easily. It also helps reduce odor after long use. Most plain opal glass cups are microwave safe and dishwasher safe. Tempered opal glass cups are more resistant to chips, scratches and daily knocks than regular glass cups. They are lightweight and easy to handle. They are also strong enough for homes, cafés, restaurants and hotels. If you choose cups with gold rims or metal decoration, please confirm microwave use before ordering.