Power spraying distributes a large amount of water in a short amount of time. Protect nearby plants and grasses from the hard spray by placing plastic sheeting over the adjacent lawn or flowerbeds. Remove any vines that twine around the wrought iron fencing. Use the plastic sheeting to cover painted areas of adjoining wooden walls or structures to avoid damaging these other surfaces.
Check the integrity of your wrought iron before power spraying it. Wrought iron fences contain forged and welded steel. Although this material is resilient and sturdy, weak joints and areas of improper welding may buckle under the pressure of a power sprayer. Avoid directing the spray toward any weak areas along your fence. Rather than spraying these delicate areas with the power sprayer, use a small bristle brush to scrub the surfaces gently.
Removing as much rust and chipping painting as possible before spraying will reduce the amount of water and pressure necessary to create a bare finish. Spray a mild detergent over the surface of the wrought iron and scrub the surface with a small sponge or brush. Use the power sprayer to remove only the most stubborn areas of rust and paint.
Start cleaning the wrought iron with the lowest setting on the pressure sprayer. Adjust the setting to the minimum level required to remove the rust or paint from your wrought iron fencing. Using the lowest possible setting will help protect nearby areas from overspray. Use a fine spray pattern around detailed metalwork to remove the debris and rust from these narrow crevices. Apply a rust-proof product that contains phosphoric acid to any remaining areas of rust. This substance helps remove any rust left behind after power spraying.