It's one of those minefields because sheep flocks are endemic with e-coli, and it's the bad one
So those who work with wool, sell wool, etc., don't sell unwashed wool if they have folks best wishes to heart.
If you skirt and remove the dags from a fleece and put that into a big bucket of water and just leave it alone, it'll make a brilliant fertilizer until the gunk has all decayed and dissolved. Then you can just remove and wash and use the wool as normal. Wool does very well wet.
I don't like this idea of using the wool on the garden because all that does is allow the moth larvae that eat wool to feed well and produce more wee moths.......and eventually all those hungry moths will find your carefully spun and woven stuff indoors too
Anyway, its not hard to wash wool, it's supposed to be washed, the sheep produces stuff called suint, like wee flakes of greasy dandruff, that when soaked helps lift the dirt out of it's fleece. Just soaking the fleece in water will remove a tremendous amount of gunk just by letting the suint do it's work. That's how fleece was prepared in the past. Only if it was to be dyed did it get a wash with ammonia in the water. Ammonia is a brilliant de-greaser, and the fleece needs to be de-greased to dye it unless you're using alkanet. There's always a smell after any of these processes though.
To remove the worst of the miasma of sweaty sheep..... Shampoo is meant for hair, wool is just a crinkly hair, shampoo, just cheap generic supermarket 1ltr for £1 stuff works fine. Soak, don't scrub, rinse, rinse, and peg out in chunks to air dry. Store in old pillowslips or linen bags.
Re-lanolinising is easy, but the lanolin always has a smell. Most people use baby oil or such like for indoor clothing these days. It works, doesn't damage the fibres, doesn't (generally) irritate our skins even if it's not as natural as the lanolin.
Best of luck with it, interested to hear how you get on.
Somewhere I have handspun v. dark brown St. Kilda fleece, not enough for a jumper, I gave up trying to knit it (and if you've ever handspun enough 3ply worsted yarn for a jumper and given up, you'll understand how frustrated I was) as an aran and ended up knitting socks with some of it. There's certainly enough left for more socks, a hat and mitts though.
cheers,
Toddy