Most Effective Cleaner: Harpic Power Plus Toilet Cleaner's Better and Thicker Formula Provides 10X Cleaning, Leaving Toilet Perfectly Clean, Shiny, and Disinfected. Harpic Power Plus Toilet Cleaner Removes Yellow Stains 10X Faster Stains Caused by Hard Water feces stains Stains caused by urine, soap, or oil Dirt and rust stains Kills Germs: It kills 99% of germs.