Rabbi Aryeh Lebowitz

But there are a lot of people that will not self-clean their oven.

They'll look for any other way to kasher it.

They will not self-clean it because they know that it's going to break.

But you see that mentality that Chazal were aware of, that if you're concerned that something is going to break, then you're not going to really want to do that method of kashering.

And this is Paschal and Ilchus Pesach.

Regardless of how you used your klicharis in the past, it does not work to do a libon.

That we're afraid you're going to have Rachmanus on the kli, you're not going to want to break it.

So that is type of kli number one.

Type of material number two is glass.

There is a machlokas, whether glass has a din like pottery, because it's made from sand, and therefore cannot be kashered, or if glass does not baleah at all, it doesn't absorb anything at all, and therefore is never a problem to begin with.

Shulchar, churuch, pesach, taftun, alef, siv, chavav, paskins,

Just rinse it off and it's fine.

You don't need any on glass.

However, the Ramas says that there are those that are

all the way in the other direction.

Not only does it need to be kashered, you can't even kasher it.

Not only does it become treif, there's nothing you can do about it.

There's no way to solve it.

It's like a klicheres.

So min ha-kotzeh la-kotzeh.