Dip the tip of an empty Swiffer Wetjet solution bottle into boiling water for about 10 seconds and the lid twists off (use a towel). Refill with your preferred cleaning solution at appropriate dilution *and re-cap.
Best grout cleaner out there and its for carpet! Resolve carpet foam. Spray it on. Leave for 10 min. Scrub it off with a stiff scrub brush! Wha la!! :)) Tip:as you scrub wipe the dirt that comes up off. If you don't it will just soak back in before you get back to mop it off.