How do you kasher a liver at home?
The issue of kashering a liver is the blood that is absorbed in it. The way this is removed is by a process of grilling over a fire.
If a whole animal liver (beef or calf) is to be kashered, deep criss-cross cuts should be made throughout the liver in various places. This will facilitate the flow of blood out of the liver. The cuts should lie face down, during the broiling. If the liver is cut into slices, no cuts need to be made, and there is no need for cuts for chicken or fowl liver (see Shulchan Aruch, Yoreh De’ah 73:1-3).
The liver must be thoroughly washed off in cold water (Yoreh De’ah 76:2; see Shach 19) and placed on a grate of fireproof material, which is made so that it does not inhibit the free flow of blood or other juices from the liver. The blood and juices should drip or run to a place where they have no further physical contact with the liver. It is preferable to lightly salt the liver before grilling begins, but this is not compulsory (Yoreh De’ah 76:1).
The fire should be directly below the liver if possible. The grilling should continue for half the time that it takes to roast the liver – if it takes an hour to roast the liver, kashering will take half an hour (Rema 73:2 and Shach 3; Peri Megadim 73:14).
The pan that catches the blood becomes treif, and the rack or grate should not be used for anything except kashering liver. Utensils used in the process should likewise be set aside for the process of kashering liver. It is meritorious practice to kasher the utensils between uses, and this can be done by placing them in the fire after the liver is kashered (see Rema 76:4; Taz 10; Darchei Teshuvah 34).
The kashered liver is washed off under cold water three times in order to remove the salt that has absorbed the blood, and any blood found on the outer surface of the liver (73:5; 76:3). If these procedures have been followed, and red juice exudes from the liver interior, the liquid is not considered blood, and is permitted to be eaten.