The most effective enzymatic cleaner for old or new urine stains from pet accidents is Nature’s Miracle. The natural bio-enzymatic formula activates on contact to eat away urine proteins and salts over time, permanently eliminating odors. For best results, thoroughly soak the affected area then let sit for 24 hours before blotting excess moisture and allowing carpets to air dry. The extended dwell time allows enzymes to fully break down stubborn compounds.