We often get asked for sources of products that we do not sell - things like cleaning products for raw copper. We use a variety and we generally don't endorse one over any other. See below for links.
Note: Follow manufacturer's instructions carefully!

Copper protecting waxes, cleaners, cloths, and adhesives
Renaissance Micro-Crystalline Wax Polish BRIWAX Wax Paste Premier Copper Products W900-WAX Copper Cleaner and wax for sinks and copper counters Flitz Metal, Plastic and Fiberglass Polish Paste - Cleans and protects for up to 6 months
Wright's Copper Cream By Weiman 8 Oz Bar Keeper's Friend Tarn-X TX-6 Tarnish Remover, 12-Ounce Brasso Metal Polish
Flitz metal polishing cloth Thieves cleaner - may be used on waxed copper without removing the patina Mr Metal polish and tarnish guard Copper polishing cloths
Liquid Nails Construction adhesive - for applying copper fence caps and backsplashes Loctite PL Premium Polyurethane Construction Adhesive - for applying copper fence caps and backsplashes Behlen Brass Lacquer 13 oz.