How to Make a Microwave Kosher
Our nanny heated up non-kosher soup in our microwave. Can we make it kosher again?
The Aish Rabbi Replies
A microwave has a unique status in Jewish law. It heats up food, but it has no actual fire in it. As a result, it is somewhat easier to be made kosher. The only concern (other than actual spills of non-kosher food) is the steam which may have been emitted from the hot non-kosher food and which might have been absorbed into the surface of the microwave.
The general principle with making vessels kosher is that the same manner of cooking which caused the non-kosher taste to go in can be used to bring that taste out. In this case, your microwave absorbed non-kosher via hot steam. Thus, the way to kasher it is to boil hot kosher steam in it, thereby drawing the non-kosher taste out. This is possibly only effective 24 hours after the non-kosher was cooked in it. There are also those who say that this does not help for the glass tray the food container sits directly upon.
Thus, to make your microwave kosher, do the following steps:
- Wait without using your microwave for 24 hours since it was used to cook non-kosher.
- Clean it out thoroughly from any spills or other food residue.
- Boil a cup of hot water in it – long enough until it fills with steam.
- Either replace the glass tray or cover it for future uses.
(Source: The Laws of Kashrut by R. B. Forst, pp. 232-34, 355.)