I’ve scoured around 40 raw fleeces so far this summer. I actually love the process - I find it really soothing.
There’s no one single “right” answer but I usually do:
One soak in cold water with Fairy liquid (to loosen dirt) - 30 minutes
two soaks in hot water of at least 140F with Fairy liquid - 15-30 minutes each, no longer
two rinses in plain warm water (maybe a squirt of white vinegar if the fleece is whiffy) - usually about 20-30 mins each
This process works the best for me - I’ve tried many different permutations! If the fleece is really filthy I might need an extra rinse but it’s rare.
There are other detergents you can use such as Unicorn Power Scour but they’re a bastard to get hold of. Fairy liquid - not a cheap knockoff - is regularly used by people who process fleeces professionally because it’s good at cutting through grease, which is what you want.
Don’t use anything with biological agents as you’ll damage the fleece.
Don’t do the Fairy scours in hot water for longer than 30 mins as otherwise the lanolin will settle back into the fleece and harden. The goal is to melt the lanolin off the fleece and tip it away with the waste water.
Some people spin “in the grease” which means keeping the lanolin but most others prefer to strip the lanolin out. The lanolin makes it feel quite sticky so it’s not very pleasant to knit with, imo.
Really important - a combination of hot water and wiggling the wool around (agitation) will felt the wool. Poke it into the water - with enough room for the wool to spread out - and leave it until you’re ready for the next step. No swishing it around in the water!
I find pressing the wool gently on a wire table between washes/rinses gets rid of the dirty water the fleece is holding, without it felting.
Don’t plunge it into cold water when it’s just come out of hot water as this shocks the wool and makes it felt. Going from cold water to hot water is fine.
Umm, what else ….
Oh yes! You mention sheep poo. Where you can, cut the really dirty bits off before you start scouring. Heavily soiled bits won’t wash out and all that happens is the dirt gets distributed through the rest of the wool and contaminates it all! Be ruthless before you start and you’ll end up with clean fleece that you can use.
Dog brushes are perfect if you want to card the wool. If you want to comb the wool instead you can use onion slicers (about £3 for two on Amazon).
Hope this helps - good luck, I love that you’re doing this!!