I used to pick out all the poo by hand.....wearing gloves obviously, lol, then
as the above post said, throw the bed up against a wall, brush out the wet and relay the bed.
However, IF you are thinking about changing bedding consider Aubiose rather than shavings.....you deep litter, so just need to poo pick day to day and then have a 'bigger' clearout in the same manner as the shavings, once a week.
Its fantastic stuff, very absorbent, and although intitially a bit dearer by approx £1. per bale, saves you loads and loads of time in the longrun.
I was adding shavings by the ton it seemed when I was using them but since
changing to Aubiose only usually need a bale a week, two if I am feeling really generous. Once you have laid the bed you 'water' it and it forms a sort of crust that the wet soaks down through. Fantastic Stuff......Easybed
is similar. I would never willingly go back to shavings now.