Good morning.
Part of the preparation for Pesach (Passover) is to make sure that our kelim (vessels) are clean. Clean up chametz (leavened food).
As you know, when a person cooks in a pot or roasts with a keli (vessel), the pot or vessel takes a ta'am (taste) from the thing he’s cooking. So, of course, a person who uses pots all year long with chametz cannot use those pots on Pesach, as they have swallowed chametz during the year. Therefore, when you cook with them again, the chametz comes out. So what is the process of koshering things? We have a rule: the same way an item swallows, you get rid of the thing it swallowed inside.
For example, the Shulchan Aruch says, “Vessels that are used through fire.” For example, you have skewers. Skewers, you don’t use them with chametz. You do it directly on the fire. So if you use skewers with chametz on them during the year, how do you clean them? How do you get rid of the chametz? You have to do libun, which means you have to take a fire, put the fire in the skewer, and he says, “Until sparks”; it has to get very red, right? I don’t know how you would do it today. You would have to take some sort of blowtorch. They actually have a place on Avenue L, I believe, where they do it for you. That’s the only way to get rid of chametz. That’s the only way to get rid of chametz on items that were used on the fire. You have to apply fire, and a very strong fire, to get rid of the chametz that’s inside.
Now, with cooking—for example, a pot—the way to get rid of the chametz in the pot is to do Hag’ala, which means you take a very big pot of hot water, and you put your pot in there; you put it in.