Keep in mind that cats wont use a messy smelly litter box so scoop solid wastes out of the box at least once a day. Clean the Box. Cat Pee Smell Remover Diy Enzyme Cleaner For Cat Urine Cat Pee Smell Cat Urine Smells Cat Urine If your cat will not use a litterbox please consult. . This means jettisoning the old litter scrubbing the empty box with mild dish soap and warm water rinsing it with clean water letting it air-dry and pouring in a fresh supply of clean unscented litter sometimes scented litter is unappealing to finicky cats. First and foremost scoop clumps from the litter box daily and deep clean it frequently. You can do this less frequently if using clumping litter. Dont use ammonia deodorants or scents especially lemon when cleaning the litter box. Dump everything wash with a mild detergent and refill at least once a week.