OMG....Well, when you go for spinning you go the full mile.
Step 1) Sort the fleece
Skirting the fleece - shake it, remove the really yucky stuff at the rear end. Remove the second cuts (sheared twice short parts)
Then sort by the dirtiness factor. Pile for really dirty to fairly clean. This prevents dirtying up your clean wool in washing.
You can go further and sort by finess or fiber quality. The best wool usually comes from the top shoulders behind the neck. Then just to either side of his back bone.
Step 2) Only wash a pound or two at a time. Place in mesh bag.
Avoid agitation or temp changes, running water on wool....wool felts even in this stage.
Use mild dish detergent no laundry soap.
Step 3) Dry it on mesh racks or something similar
Then all the carding, combing or picking begins....
If it were me, I'd look into sending it to a mill. I'm lazy that way though.
And you've got to let me know how this turns out! You've got a project and half ahead....