Toilet Bowl Cleaner Strips - Just Drop, Brush, Flush!Nature Clean Toilet Bowl Cleaner Strips in plastic-free packaging are pre-measured, easy to use, and easy to store. They are scented with essential oils only and are non-toxic, biodegradable, and septic tank and grey water safe. Just drop one strip dark side down into your toilet and let dissolve for 30 seconds, then brush and flush for a clean that is tough on dirt and gentle on the environment.