This is the procedure to be followed:
1. Make sure to perform the hagalah before the end of the fourth hour of the day before Passover. This end of fourth hour time is the same as the time that is announced to stop eating hammets.
After this time, and throughout Passover itself, only libbun gamur or libbun kal may be used to kosher utensils.
2. Make sure that the utensils to be koshered were not used for twenty-four hours.
3. Make sure that the pot or other vessel in which the water is to be boiled—was also not used in twenty-four hours.
If utensils which had been used within 24 hours must be koshered, one should place soap or bleach in the water as it is being boiled. This renders any taste which is emitted—inedible, and has the same effect as waiting 24 hours.
Note: If all of the above steps are followed, a meat pot can be used to boil the water, even if dairy utensils are to be koshered, and a dairy pot can be used—even if meat utensils are to be koshered.
4. Clean the utensil thoroughly, being especially careful to reach portions of the utensil which are hard to reach, such as, in the case of a pot, the space where the handle meets the pot itself.
5. Boil water in the pot or other vessel which will be used for the hagalah.
6. Pour the boiling water over the utensil to be koshered.
Be certain that the water touches every portion of the utensil or counter. The water cannot be poured on only a few locations and then allowed to flow over the other locations. Rather, it should be poured directly upon each location.
Be certain that the stream of water from the pitcher to the item being koshered—is uninterrupted. In other words, tipping over the pot containing the hot water in an abrupt motion is not good, since it produces an interrupted stream of water. Rather, the pouring motion should be less abrupt and more steady, producing an uninterrupted stream.
Do not transfer the water from the pot it was boiled in—to another vessel, such as a pitcher, before pouring. The water must be poured from the vessel it was heated in.
7. Place the utensil which was koshered into cold water. This may be done by having a pot of cold water ready and dropping the utensils into it as they are removed from the boiling water. Alternatively, one may pour cold water upon the utensils which were koshered.
Points to Keep in Mind about Hagalah by Pouring
On Passover itself (during Hol Hamoed, the intermediate days), libbun gamur or libbun kal—may be performed, while hagalah and hagalah by pouring may not be performed. Therefore, if one has a utensil that is normally koshered by hagalah, and the individual wishes to kosher that utensil on Passover from hammets to Passover use—it should be koshered by libbun gamur or libbun kal.
There is no beracha upon hagalah by pouring.
Once a utensil is koshered for Passover use, it emits everything which is absorbed in it. Therefore, one may use a utensil which was previously “meat” for “dairy” and vice-versa, after koshering the utensil for Passover use.
For a comprehensive A-Z listing of how to kosher various utensils and appliances for Passover, click here