Urine stains can happen any time, so you have to keep a vigilant eye on your dog's coat. He could accidentally soil himself, roll in urine-soaked grass or even step in a urine puddle that soaks the fur around his feet. While it's easiest to remove fresh stains, there's still hope for dried, set-in discoloration -- it just takes a little more elbow grease.
Brush the urine-stained area thoroughly. This removes dead hair and any loose debris that could be in your dog's fur, allowing the water and cleaner to reach the coat more directly. Use a breed-appropriate brush for the best results -- for example, use a slicker brush on a poodle, or a short-bristled brush for a short-haired dog.
Spot-treat the urine stain by gently scrubbing with either a warm, damp washcloth or a fur-cleaning wipe from the pet store. You may try mixing in a little dry groomer's shampoo -- this is what groomers and dog show participants use for waterless cleaning. If that doesn't do the trick, it's bath time.
Wash your dog using a dog shampoo formulated for his fur color. For example, white dogs -- who are especially prone to urine staining -- should be washed with a shampoo formulated for their coats. These shampoos may include a blue coloring agent that negates and effectively reverses the yellow stain. Use the shampoo according to its instructions.
Consult with a groomer if shampoo isn't taking out the stain. Homemade stain removal solutions can harm your dog's skin or eyes, and may be more harmful than shampoo if accidentally swallowed. If scrubbing the stain in a bath doesn't remove it, your dog needs professional care.