Is unripe produce (boser) crushed in a chametz mortar before Pesach permitted on Pesach, and what about cutting with a chametz knife during Pesach?

Synopsis

The Mechaber permits boser crushed in chametz mortars before Pesach. The Rema permits it even during Pesach if the vessel is clean, but forbids cutting with a chametz knife on Pesach since an ordinary knife is presumed not clean. If the knife-cut item gets mixed into a cooked dish, we are not strict.

Early Acharonim
Lenient
Strict
Lesser cited
Major authority

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