I bought a pack of livers – within how many days must I kasher them. If after five days can I eat them
Essentially it should be kashered within 3 days, the reason being that if it is kashered after 3 days it may not be cooked afterwards. After three days you may still kasher the livers, by roasting them (livers may never be kashered by merely salting), however they should not be cooked afterwards. In retrospect if the livers were already properly roasted after three days and then they were cooked, it is still permitted to eat.
Y:D 69-12, 73-1, Pischei Teshuva 69- 26.