Likely the best lube I found coming from an animal, is marmot oil. This is fried out from the interior oil, fat from about the organs - absolutely the oiliest
fat I have ever handled. Mind you, these animals were shot in very early October & had a full winter's fat on them. These mountain maggots were very
tasty indeed. After handling the fat, I had to wash my hands in dish detergent twice to get the oil off my hands.
Pre-cuts in a plastic bullet box, pour oil over them, squeeze the stack to drip back into the jar, wipe hands on shop rag, then wash twice. If using a WD40
spray (hose down) on the hands first, then only 1 washing was needed with the dish detergent.
It sure worked well in the .58 with those big charges I was using back then.