Yes, you need to lanolize.
Get some Lansinoh, like they sell for sore nipples, and squeeze a few inches into a coffee mug. Fill the mug with boiling water and stir to dissolve the lanolin. Then fill a clean sink with lukewarm water. Pour the dissolved mixture into the sink and then turn the covers inside out and plunge them into the water. Swish them around a lot and squeeze the water through the wool gently, then let them soak awhile-- maybe ten minutes??? Then take them out and squeeze the excess water out, blot them between towels, and then lay them flat to dry. If you want speedier drying, hang them over a fan that you turn on high.
If you're doing a lot of covers, use more lanolin than a few inches. About two inches for each cover I'd say.
The covers may feel pretty sticky with lanolin at first. That's okay-- baby's skin will absorb the excess.
I relanolize every time I wash; for me, it's just part of the process. But I'm washing very infrequently, like every two months. If you're washing more often, you might only need to re-lanolize occasionally. You know you need lanolin when the covers are leaking wetness even though the diaper underneath isn't saturated yet. (If the diaper is totally saturated, even a well-lanolized cover may leak a bit. The pee has to go somewhere!)
When I wash, I use Dawn dish liquid. Wash in a sink of cold water. Don't rub or wring too hard-- you'll shrink and mat the wool. Make sure the detergent is all the way rinsed out, then lanolize.
You can also spot-clean like if food gets on the cover or something-- just use a wet washcloth to swab the offending spot. I only wash my covers if they get poo on them or if they start to smell like pee when they're dry. (Wet wool will smell like a dog that got caught in the rain, even though it's clean-- natural and normal. The smell will go away when it dries.)
