B&B dagging shears, as and when required (which with mine is very rarely).
Don't try and cut through the poo. you need to cut lower than that, so you are cutting the clean wool underneath (not the skin mind

). Sometimes you can if it's still wet, but you won't be able to if it's dry and you are using dagging shears. Foot trimmers are ideal if you do have a bit that you need to cut through though.
The only other time I use my dagging shears is to trim the ewe-lambs wool in front of the back leg, pre-tupping, so that the udder is more accessible for the lambs come the spring.