Introduction
Copper is a beautiful metal that is commonly used for exterior architecture, roofs, gutters, and decorative accents on homes and buildings. However, outdoor copper is susceptible to weathering and oxidation, which can cause discoloration and corrosion over time. Learning how to properly clean and maintain your outdoor copper can help restore its original brilliance and prevent further damage. With the right techniques and products, keeping your outdoor copper fixtures looking their best doesn’t have to be difficult.
Assess the Copper and Identify Problem Areas
The first step in cleaning outdoor copper is to thoroughly inspect each copper fixture or surface. Look for any areas that are especially dirty, stained, or corroded. Check gutters, downspouts, railings, and architectural details for green oxidation, black streaking, white powdery deposits, or brown staining. Identifying problem areas will allow you to focus your cleaning efforts where it is needed most.
Pay particular attention to recessed areas, undersides, and any locations that tend to collect dirt, grime, and moisture. Northern and western exposures on a home will often experience the most weathering. Make notes on the areas that need priority cleaning so you can tackle them efficiently.
Remove Loose Surface Dirt and Debris
Before using any cleaners or chemicals, do an initial cleaning by removing all loose dirt, grime, leaves, and debris from the copper surface. This can be done with a soft brush, microfiber cloth, or gentle pressure washing. Avoid abrasive scrubbing at this stage, which could scratch the copper finish.
Be sure to completely clean out all corners, crevices, details, and undersides. This will prevent loose contaminants from interfering with your heavier-duty copper cleaning later on. Proper surface preparation is key to achieving the best results.
Choose Your Copper Cleaner
There are several effective cleaners and chemicals that can be used to brighten outdoor copper:
- Phosphoric acid-based cleaners – Sold under brand names like Klean Strip Green or Copper Brite, these mildly acidic cleaners work to dissolve oxidation and restore copper’s original finish. Use caution when handling the acidic formula.
- Oxalic acid solutions – Often found in wood bleach products, oxalic acid can remove stubborn oxidation and staining. It is a more aggressive chemical than phosphoric options. Exercise caution with oxalic acid cleaners.
- Mild soap and water – For lightly soiled copper, a basic soap and water solution may be effective. Opt for mild detergents free of additives and fragrances. Avoid abrasive soaps.
- Ammonia – Ammonia is useful for removing thick tarnish buildup on copper surfaces. Use a diluted 10% ammonia solution for best results. Never mix ammonia and bleach solutions.
Start with the least caustic cleaner needed for the job. Test cleaners first on inconspicuous areas to ensure compatibility with your copper and determine the ideal dilution if needed.
Apply the Copper Cleaner
With your chosen copper cleaner in hand, work in manageable sections systematically covering each area of the copper needing cleaning. Follow all product instructions closely, applying the cleaning solution liberally to soil deposits, green oxidation, or stain buildup.
Let the cleaner sit and work into the stains for the recommended dwell time before wiping or rinsing. This allows the active ingredients to fully penetrate and lift the oxidation and grime. Reapply cleaner to stubborn areas as needed until the stains have lifted.
Take care applying cleaner to decorative copper areas with fragile patinas or finishes. Use a gentle touch and test on small sections first.
Scrub and Wipe Away Residue
After the cleaner has had time to work, use a soft brush, sponge, or microfiber cloth to gently scrub away the dissolved oxidation and grime. Take care not to scratch soft decorative copper finishes.
Rinse thoroughly with clean water when done. Wipe the copper completely dry to prevent water spots and mineral deposits. Reapply a small amount of cleaner and scrub again if any residue, staining, or green oxidation remains. Work patiently to fully restore the copper.
Apply Copper Protectant
Once your outdoor copper fixtures are freshly cleaned and dried, apply a copper protectant sealant to help maintain the renewed finish. Options include:
- Clear varnishes – Clear, matte, or satin varnishes create a protective barrier against corrosion. Multiple coats may be needed for full coverage.
- Automotive and boat waxes – Waxes containing carnauba create a protective finish that adds shine. Apply wax evenly in thin layers.
- Metal polishes – Special copper polishes help seal out moisture and prevent tarnish recurrence. Use a small amount, buffing gently with a soft cloth.
Follow manufacturer’s instructions, allowing proper dry time between coats. Reapply protective sealants as directed to maintain protection. The preventative barrier helps retain copper’s beauty.
Maintain Copper Regularly
Get in the habit of inspecting and wiping down your outdoor copper fixtures regularly. Use a damp microfiber cloth to lightly clean surfaces weekly or as needed. This regular maintenance helps limit oxidation and staining.
Annually assess if a full cleaning is needed, repeating the process for any new problem areas that have developed. Stay vigilant against damage from sprinklers, runoff, bird droppings, and other environmental hazards. With proper care, your copper can maintain its original brilliance and patina for years to come.
Frequently Asked Questions
How do I clean green oxidation off copper?
Phosphoric acid cleaners work well to remove green oxidation. Apply the cleaner and allow it to sit for 5-10 minutes before scrubbing and rinsing away residue. Reapply as needed for stubborn deposits.
What homemade solution removes copper stains?
A paste of lemon juice and salt or a diluted vinegar solution can help remove light copper stains without harsh chemicals. Scrub gently, rinse thoroughly, and repeat if needed. These natural options may take more elbow grease.
Will pressure washing damage outdoor copper?
Pressure washing can damage delicate copper if not done properly. Use the lowest pressure setting and keep the nozzle at least 12 inches away to prevent scratching or driving grime further into the metal. Move continuously to avoid excessive pressure in one spot.
Should copper roofing or gutters be sealed?
Sealing copper roofs and gutters is not necessary or beneficial. The metals develop a natural patina over time that protects against corrosion. Cleaning alone is typically sufficient maintenance for roofing copper.
How often does outdoor copper need cleaned?
Light maintenance cleaning can be done every 2-3 months on outdoor copper. For a full, deep cleaning, plan to clean copper fixtures at least annually or whenever heavy oxidation, staining, or residue has built up. Cleaning frequency depends on environmental factors.
Conclusion
Outdoor copper requires periodic cleaning and sealing in order to maintain its aesthetic appeal and prevent deterioration. By using the proper cleaning products and techniques, you can safely remove oxidation, restore original patinas, and protect copper surfaces from future corrosion. Make copper cleaning a regular part of your exterior maintenance schedule for optimal results. With a little time and effort, your copper fixtures can retain their natural beauty and durability.