Remove Urine stains with white vinegar
Blot up as much of the excess liquid from the material as you can by laying the material on the floor and using a few paper towels.
Soak in cool water, mixing and stirring the material in the water and then let it sit for about an hour. If the stain is really old, soak for a few hours longer.
Launder as usual in a warm water, never using hot. Hot water cooks the vomit on the fibers of the materials.
Check the stain, if it remains in the material, launder again before drying.
If the stain continues to persist, soak in a bucket of cool water and add three cups of white vinegar, letting this soak over night.
Launder again, in warm water and then check the material for any remaining stains.
If the fabric allows, wash with color safe or chlorine bleach per the instructions on the tag to bring out any tough remaining stains.