Fresh Lube pump oil exhaust freshener from Surco Products is designed to counteract offensive exhaust odors generated by portable restroom and septic vacuum trucks. Its oil-based Metazene molecular odor neutralizer mixes into pump oil without damaging it. Add 4 ounces to each gallon of pump oil, and foul exhaust odors are replaced with a pleasing cherry-drop fragrance. 800/556-0111; www.surcopt.com.