Review on Hercules 35100 Boiler Cleaner by Josh Garber

The powder hardly penetrates the boiler. It takes a large funnel to do this, but when heated it binds to rust and forms a black precipitate that is easily washed out through the drain valve. Continues to rise, slightly raising the boiling point, creating hot, dry vapor. Also reduces the hammer effect. (Of course, half a pound of pressure reduction helps here too. Have used it successfully for decades. My old boiler has been running for over 55 years.