Will not harm plumbing.
3 LB PACKET, 2PK Concentrated powdered toilet bowl cleaner compound quickly dissolves in water to produce a cleaning dilution that can be varied to meet your needs.. Pleasant scent.Application: Restrooms; Applicable Material: Ceramic; Fixtures; Metal; Painted Surfaces; Wood; Chemical Compound: Sodium Chloride; Dirt Types: Organic Waste; Urinary Salts.