Chandelier sleeves, or candle covers, are placed under each light bulb in the piece to give that chandelier a vintage look. Some are just simple tubes of white paper, while others are made of synthetic beeswax so they look like real candles. The more elaborate versions also have wax-drip designs running down the sides, mimicking the days when real candles were used instead of electric lights. Sleeves are available for standard and candelabra-sized sockets.
Chandelier sleeves are also made of plastic and metal and come in different colors. These are often used in modern decor because of their clean-lined, polished look. The metal variety is particularly shiny because of the enameled look of the paint.
Candle covers are also used on sconces, or decorative wall lights. The trick with the sconces is to get a candle sleeve that matches not only the wall lights, but the centerpieces they sometimes highlight. Sconces from the Edwardian period, which are sometimes reproduced, are known for their candle-like twin lights, sometimes topped with shades.
Since the sleeves wear out over time, usually from collecting dirt and dust or from heat exposure, it's advisable to replace all covers at the same time. Usually it's a matter of unscrewing the light bulb, sliding on the cover, and then putting the light bulb back on.