Often sold in clamshells or as small scalloped shaped discs, wax tarts are meant to be melted in a tart burner or melter. Some are electric and some require a tealight in the bottom. The electric melters are advantageous for spaces, such as dorm rooms, where candles are prohibited, or in homes with curious pets and children. This does not, however, mean the melter can be left unsupervised, because it could easily be knocked over, causing burns to a pet or child from the molten wax.
To burn the tart, remove it from the wrapping and break it into pieces to fill the well in the top of the melter. One great thing you can do is combine 2 or more scents for a custom fragrance! Do not overfill the melter well, as the melted wax will overflow. A single round tart, or a few pieces from a breakaway bar, should give you plenty of aroma. Next, turn the melter on or light the tealight underneath, soon, you should have a comforting aroma eminating from your melter.
Many times, the scent from the wax will fade before the wax evaporates, meaning you will need to empty the well of wax and add fresh, scented wax. Never dump the old wax down the drain. It is easiest to clean when the melter is cool and the wax is hardened. Simply take a knife and pry the old wax from the bottom. It should come out easily. Then wipe the melter well with a towel before refilling.
So why choose tarts over traditional candles? Myself, I prefer traditional candles with a flame, but there is no denying that wax tarts are much more affordable than buying a large candle! This allows you to try multiple scents for a small price. Also; you can combine scents and rotate the scents often if you get bored with the same fragrance.
The brand name Scentsy is becoming very popular, offering many styles and models of tart melters and a wide variety of scents, but don't forget the handmade tarts and melters out there. There are many potters who can make a ceramic melter and many home crafted varieties of tarts for sale on line or at craft fairs. In fact, the Scentsy company was born when a husband/wife investor team discovered wonderful, handmade tarts at a craft show.
If you are interested in making tarts, the link above sells all the materials you need and there are plenty of tutoials online. A word of caution is that trying all the scents is highly addictive and it is doubtful you will save any money by making your own, because you will soon be purchasing many, many new scents to try. Aroma Haven/Rustic Escentuals, for example, offers over 300 scents and at least 5 kinds of wax to try for your tarts!