Metal pieces made of brass, silver, and copper add warmth and elegance to any room. Over time, however, they're bound to lose their luster, developing a layer of tarnish. Even in optimal conditions-a cool, dry setting out of direct sunlight-tarnish can't be avoided. That's because it's caused by the reaction between a metal object and its environment. While tarnish itself isn't harmful, it can be unsightly. Luckily, it's easy to polish away. (Though a little patina is sometimes desirable, too.)

You'll want to take extra care when it comes to copper. Cleaning it can be especially tricky - if you scrub it too hard, you can scratch the copper and remove the finish. In order to safely and properly clean and polish this metal, we've enlisted the help of Leslie Reichert, green cleaning coach and author of "The Joy of Green Cleaning," to compile tips using chemical-free products for effectively cleaning a wide array of copper products.

Before you get started, Reichert suggests checking to see if your copper has been sealed. If so, you will not want to clean it using the methods below. "The sealant could be an oil or a lacquer that was applied to prevent tarnishing. Cleaning the copper with a paste or even a lemon juice/salt mixture could completely remove the sealant."

For items that aren't coated in a sealant, these treatments for cleaning copper amaze everyone who tries them, restoring the natural vintage charm of even the most tarnished copper wares.

Gather Your Ingredients

Below is a comprehensive list of products you would want to have on hand to prevent tarnish, clean copper, and remove tarnish, according to Reinhart.

Baking soda

Lemon juice

Salt

Vinegar

Ketchup

Baby oil

Orange juice (as an alternative)

Baking Soda for Deep Clean

Note: Baking soda works well for spots that need a little extra attention like the bottom of copper cookware. "The baking soda can be sprinkled on the area, followed by the use a sponge with warm water to gently go over the spot. Don't be too aggressive–you don't want to scratch the copper," says Reichert.

Using Lemon Juice and Salt to Remove Tarnish

Lemon juice and salt are useful for removing tarnish from copper in three easy steps:

Squeeze the juice of the lemon in a bowl and then sprinkle the salt into the juice. Reichert does a 75:25 ratio, with three times as much lemon to salt. Stir for a minute until the salt dissolves. Dip a cloth into the solution and wipe the copper.

"It's magic how it immediately removes the tarnish. I use this method instead of dipping the lemon in the salt to prevent the salt from scratching the copper," notes Reichert. Additionally, she advises that if you don't have lemon juice, you can use orange juice as it is also acidic.

The Quick Clean Method

"If you have a large copper item and you want to clean it quickly, you can boil three cups of water, add a cup of vinegar and one tablespoon or more of salt," says Reichert. Next, you would stir until the salt is dissolved and then place the copper item in the water. "The tarnish will come right off."

Reichert details the process to use if you want to use more of a rubbing action for cleaning copper. "You can use ketchup and spread it all around the copper. The acid in the tomatoes will remove the tarnish. After rubbing it all around the item, make sure to thoroughly rinse."

Prevent Copper from Tarnishing

"You can prevent the tarnishing of copper by wiping a light coat of baby oil or mineral oil over it right after cleaning," says Reichert. She adds that you have to be very careful that the copper is cleaned completely before applying the oil. "Copper starts to tarnish as soon as it's cleaned. The oil will seal the copper from the air and slow down the tarnishing process."

Avoid Removing the Finish of Copper

Reichert recommends using the process of the liquid lemon juice and the dissolved salt to avoid removing the finish or scratching the copper. "This simple process is totally liquid and will not damage the copper surface."

How Often You Should Clean and Polish Copper