When your horse sustains a minor skin wound, your first impulse may be to spread antibiotic cream or ointment on the area. Hold off on the medications for a moment, however, and instead reach for the hose.
Flushing a wound with plain water is one of the best ways to prevent infection. (Isotonic saline solution, which you can purchase at most drug stores, is even better because it is a little easier on tissues than plain water. But from a practical standpoint, water straight from the hose is perfectly fine for your horse's wounds.)
Spend plenty of time rinsing the wound---continue for about twice as long as you think you should---and well after all the obvious 'dirt' has been removed. Keep in mind something that veterinarians often say: 'Dilution is the solution to pollution.' In other words, the more you flush a wound, the more pathogens You'll remove, lowering the risk of infection.
When you're done, take a close look for signs of dirt, grass, gravel or other foreign objects. Use a flashlight if it helps. If you see anything unusual, flush the wound again and recheck. If you can't see the entire depth of the wound, call your veterinarian; deep puncture wounds are notorious for harboring dangerous infections. Of course, visible bone, deep contamination or significant wounds over joints also merit a call to the veterinarian.
Once you're certain the wound is as clean as possible, consider applying a wound gel or ointment. But be sure to use a water-based product: If there's any chance the wound will need stitches, the ointment must be easy to remove.