Why Must Utensils be Koshered?
We answer as follows: When food is used in vessels or utensils in certain ways, some of that food becomes absorbed in the walls of the vessel or utensil. When that item is used again, the absorbed food may be emitted into the new food that is in the vessel or utensil.
In the case of hammets and Passover food: If a vessel or utensil absorbs hammets and is later used for Passover food, the hammets is emitted from the vessel and becomes absorbed in the Passover food.
How Do We Determine if a Utensil Can be Koshered?
Firstly, it depends on what the utensil is made of.
Secondly, it depends on how the utensil is normally used. In other words: How did it absorb what it absorbed?
Click on the following pages to understand these subjects in depth.