I drain it into a paper towel in a can or an empty nut butter jar if there is a lot, or if it's store bought beef. If I'm making something with a cream sauce, I'll drain it, save it, whisk it into whatever sauce/gravy I'm having. Vit A, D, K are fat soluble, not sure what amount is contained in beef fat though. Not sure if that's the best thing, thats just what I've always done...
Lard/bacon fat, now, that's a whole 'nother story. That stuff is precious.
Having said that, I'm a newbie, and still waiting for the PB book to appear in the mailbox.
*sits back on her heels and watches for other answers.*