Wikipedia
Sweat scraper
A sweat scraper is a grooming tool used on horses. It consists of a handle and a rubber blade. It is used to remove sweat from horses. It is used in much the same manner as a window cleaner would scrape water or foam from a window with a rubber blade.
Sweat scrapers are available in both metal and plastic form. The typical use of a sweat scraper is now actually to remove excess water after bathing a horse to help it cool down rather than for just sweat. Without the use of a sweat scraper, it would take more effort and additional rags to remove the same amount of excess water therefore the proper use of a sweat scraper helps to ensure an effective cool down process.