What is the sweat scraper used for on horses?

Well, they're used for wiping the sweat off of horses. When the horse has been worked hard, ie running or jumping for some time, it becomes very sweaty. It may literally drip sweat. If the weather is cool and the sweat is left to sit on the horse once it is no longer moving, it can make the horse cool down very fast. This causes cramps, muscle spasms and can cause lung infections. The sweat scraper is a flat plastic blade (not sharp) that is run along the horse's coat to remove sweat. When the layer of sweat is gone the horse is cooled down slowly. It is also used when giving horses baths in cold weather to remove most of the water before the horse takes a chill.