The qualities in the fleece you select will, to some degree impact the way you’ll need to process it.
High-grease fleeces will require washing at higher temps, and perhaps multiple washes.
Very long fleeces are not suitable to be carded (unless they are cut). Better to use combs or flick card. Very short fibers cannot be combed very effectively. Best to card (hand or drum).
If multicolored, do you want to blend for uniform color, or preserve the different shades?
Vegetable Matter (VM, veg):
Some veg may be removed via hand-picking, but you’ll get best result from combing.
Can skirt out of fleece, or dye the wool.
Matted or weak tips:
Will require trimming of affected areas.