247. Immersing Borrowed Utensils

37:4 If a utensil was previously used by a non-Jewish owner in a way that requires it to be kashered with boiling water or fire, it must be kashered before immersion.

37:5 If one borrows or rents a utensil from a non-Jew, it need not be immersed. If one borrows or rents utensils from a Jewish merchant, they should be immersed without reciting the blessing. The merchant should inform the customer who ultimately purchases these utensils that they were already immersed so that the buyer doesn't immerse them again, reciting the blessing unnecessarily.