Galvanised metal pipes are steel pipes coated with a zinc oxide compound. This coating serves as a protective barrier to help prevent erosion, rust build-up or other damage to the steel. This type of pipe is used extensively in outdoor construction because it lasts longer when exposed to the elements than regular metal materials. Periodic cleaning of the pipe helps keep the metal looking new and the coating safe from build-up of foreign elements that may lead to damage.
Brush off the galvanised pipe with a broom or soft-bristled brush to remove any loose debris that may cling to the pipe. Spray the pipe with a garden hose to remove any stuck-on dirt or debris.
Mix a solution of 1 gallon hot water and 1/4 cup dishwashing liquid in a bucket and stir it thoroughly. Use the soft brush to gently scrub at the pipe in long fluid strokes. Avoid scrubbing in a circular pattern as this could create rings in the metal over time. Work from one end of the pipe to the other, do another side, and another until the entire surface is washed down.
Fill a second bucket with warm water and use a sponge to rinse off the soap residue left on the pipe. It may take some time to remove all the soap in this manner, but the warm water rinse will better protect the surface coating than spraying with a cold garden hose.
Dry the pipe with a clean soft cloth to remove as much of the water as possible. It may take more than one cloth depending on the size of the pipe. Allow the pipe to dry for about 30 minutes.
Apply a thin coating of automotive wax to the pipe with a clean soft cloth. Rub it into the metal with a small circular motion until the pipe is covered. Let the wax dry on the pipe for the amount of time listed on the product packaging and then buff the pipe with a second clean soft cloth. This helps add a protective layer to the pipe and also fills in any minor scratches or imperfections.
To remove hard water stains, mix a distilled white vinegar and water solution and apply it to the stain with a soft cloth. Rub lightly to remove the stain.
Be careful when cleaning that you don't scratch the galvanised coating when brushing or scrubbing. If the colour of the metal changes during cleaning, stop and inspect the surface for any damage before continuing.