Red Freckles jewelry is made using many different materials including 14k gold filled, vermeil (gold plated sterling silver), Sterling Silver, brass as well as gold and silver plating. As with all metals exposed to the elements during wear and tear will endure some kind of tarnish.
For pieces that are plated, including vermeil, Red Freckles recommends not wearing them in water as that will increase the chances of the gold plating wearing off over time.
Brass pieces, such as the engraved hearts, can be polished using a brass cleaner to restore the item back to it's original luster. Sterling Silver can easily be polished using a polish specifically made for silver, as silver has the tendency to dull over time.