The Eventing Vet mentioned cleaning stud holes with WD40 but I thought I would just mention another way to make the job easier.
I discovered that stud holes are easier to clean when you have washed the horse. I now wash the horse and while its feet are still wet, I will do the stud holes. The are really easy to do when wet and then plug with cotton wool or cigarette filters overnight.
WARNING NON BHS METHOD! – I have been known on a particularly easy going horse to pick its feet up and direct the nozzle of the hose into the stud hole to clean it out which also works well!
Love the non BHS method, should work a treat with a chilled horse (though I’ll be standing back and well to the side for the first time I try it) !