Coffee Mugs

[chaimyabadi]

No unless you use them with an immersion heater. Then it would depend what its made out of
See section on koshering/Hagalah

Laws of Koshering (Hag’alah and Libun)

The utensils that we use to eat our food must be kosher. Sometimes these utensils can become unkosher as described below. There are a few methods of koshering, and one must be sure to use the appropriate method for the right utensil. One method is called Hag’alah. The idea of Hag’alah is to remove any unkosher taste that may have been absorbed in the walls of the utensil. Another method is Libun. The idea of Libun is to burn out any taste that may have been left in the walls of the utensil. A …