Wash them really well and allow to dry, then attack with the special horse razors. Run them down the hair. They go blunt quick so make sure you have heaps.
i cant be bothered with the messing about with scissors and razors anymore, i only have one thats even remotely hairy these days and i use trimming clippers and a plastic comb (metal = vibrates).
i lift the hair with the comb as if i was going to scissor trim it but clipper it of fin an upwards direction, i get a lovely result very quickly
Wash and allow to dry. Then I find trimmers the best thing. You can use a comb and scissors, but there are very few people that can do this properly without 'steps'!