Problem: I’ve washed a horse to clip him but it isn’t dry!
Solution: Hair dryer! If despite a good cooler / sweat rug your horse is still damp, plug in your hair dryer and finish the job. If they don’t mind being clipped they rarely mind this as the noise is similar and most quite enjoy the warm air on their skin! Also, if you are washing a thick coated horse adding some methylated spirits to the rinsing water will help to evaporate the water from the coat quicker.