Parallel versus Tapered Threads

Threads

Limescale Removal

Calcium carbonate (limescale) dissolves in a range of mild acids.

Rust and WD40

WD40 stands for Water Displacement, 40th attempt (name used by the chemist who developed it in 1953). Norm Larsen was trying for a formula to prevent corrosion, achieved by displacing water. WD40 has no expiration date. It also cleans and degreases and can be used to lubricate the chain on a bike. WD40 cans contain carbon dioxide as a propellant.

You can remove rust with a wire brush and coat with WD40 to prevent rust.