Stubborn stable stains mean nothing to this powerful formula. A little spray of NAF Muck Off Stain Remover on the stain will lift it clean away and your horse or pony will be spotless. So even for those stains that seem impossible, it is definitely worth a try with NAF Muck Off Stain Remover. Nothing has been found that NAF Muck Off Stain Remover can't remove.