A). Copper can tarnish with brown smudges as it is handled and exposed to the elements. The best way we have found to shine up your copper and remove the grime and tarnish is household ketchup. Submerge your copper items in ketchup for about 10 minutes, then rinse in warm water and dry with a clean cloth. If your tarnish is stubborn or your copper is porous, you can use a plastic-bristled scrub brush or toothbrush with the ketchup to remove even more. Again, after scrubbing, rinse with warm water and dry with a clean cloth.
B). Copper is capable of developing patina, the greenish oxidation from being exposed to the elements over a long time and especially in humid environments. However, natural patinas on copper can take 4-6 years in a humid environment and 10-14 years in an arid environment. If you are interested in adding the patina effect to your copper items but don't wish to wait 10 years, there are chemical rubs and treatments available that will speed up the patina development. Search the internet for the most efficient products.
C). If you would like to prevent the development of the greenish oxidation, or patina, on your copper items, you can coat your items with mineral oil. This treatment creates a barrier between your copper's properties and the surrounding elemental exposure.
If you have any other questions or comments regarding the treatment and handling of your copper niobium, please email us at: Cniobium@outlook.com If we don't have the answer to your question off-hand, we will do everything possible to find the answer for you as soon as we can.