On carding oils ... usually on a drum carder, home size, humidity and warmth should be enough. But if not, the next resort might be diluted (like, 10% of this and 90% water) unscented fabric softener. I've had alot of success with that on fly-away mohair on my mill equipment (which, ahem, is for sale if you want to open a mill of your own ...) (that's old news ... it sold :-) )
There are also oils sometimes used to control static and aid cohesion -- unscented and very diluted once again, enough that I've not noticed any oiliness in the end result, and I've had some of this roving around for a couple of years now (ok, I will spin it soon, I promise! just let me finish the stuff I bought at Madrona Fiber Festival first ...). Those, too, are mixed 10/90 with water.
I think the advice I run into online a fair bit about using things like olive oil & etc are perhaps (??) trying to mimic the industrial stuff, but don't realize how very little oil is actually needed to help control fibers. But that's pure conjecture on my part!
(posted by me this day on livejournal\spinningfiber)