The cleaning product category is where Costco's institutional pricing generates some of its most consistently compounding annual savings — and where the per-unit price advantage over grocery stores and pharmacies is most reliably dramatic. Laundry detergent. Dishwasher tablets. Paper towels. Toilet paper. Multi-surface spray. Dish soap. Trash bags. These are not exciting purchases. They are the recurring household expenditures that every household makes continuously, that nob