The best way to clean copper before application of organic coatings is the one that works for you.
Painting on copper sheet.
There are several ways to clean copper before painting.
To properly prepare new metal surfaces use mineral spirits to remove grease and apply a rust inhibitive primer before painting.
Texturize the surface of the sheet metal.
Learn how to use a simple flame to bring amazing color to copper.
Keep these layers smooth and thin by rubbing on a small amount of the lead primer with the gloved palm of your hand.
For painted surfaces that are in sound condition remove dust with a clean dry cloth de gloss the surface with light sanding and wipe with mineral spirits to ensure good adhesion.
Analyze the surface of the sheet metal.
Priming is traditional when painting on copper plate.
These oxides must be removed before painting.
Do not use alkyd based paints or oil based primer.
If painting light to moderately used indoor metal surfaces think wall sconces bed frames or guest room night tables go with water based acrylic paint a cheaper 15 to 40 per gallon.
Create a rough surface on the sheet metal.
To do this apply two coats of very thin lead based oil primer to the surface.
Acrylic metal paints are available for paint on application or in spray cans which can shorten painting time significantly.
Paints that are made for galvanized surfaces will require less prep work and will adhere better than other kinds of paint.
As with all metal painting projects proper preparation makes the difference between a quality paint job and how well the newly painted item will stand up to age and weathering especially when the metal is used outdoors.
For best practice to prepare an aluminum sheet for painting three steps are required that will provide the most assurance that both the paint will remain attached and the metal will be less prone to continue to form disturbing oxidative products on the painting.
If the sheet metal is smooth to the touch you will need to texturize it before painting.
Some people use acrylic latex paint which is not designed specifically for galvanized metal so you will want to prime the surface before painting.