bona pro 33 oz hardwood floor cleaner refill cartridge, premium no-residue formula, ready-to-use cartridge for bona hardwood floor spray mop, cleans dirty, smudged wood floors (pack of 3) bona new and improved cartridge filled with 34 ounces of bona's specially formulated hardwood floor cleaner. designed to be used only with the bona pro series hardwood floor mop, this combination will make cleaning easy, safe, and economical.