That space under your kitchen or bathroom sink is premium real estate. One way to organise your cleaning supplies without having to buy under-cabinet organisers is by installing a tension rod in the cabinet.
These cheap and adjustable rods are a great way to hang spray bottles (you probably have more than one) or, perhaps, s-hooks for other tools. It's a quick fix for spaces that are usually cramped.
Under Sink Solution: Hang Spray Bottles from Tension Rod [Apartment Therapy]