Homemade wax tarts are a fun way to use up all those old bits and pieces of candles left when the wick burns down. I also recycle my used tarts/wax bars from candle warmers.
Start by gathering used candles and other bits of wax. I have a canning jar into which I pour any wax from my wax warmers. For candles, I wait until they are completely burned, and then I have a candle warmer plate that I sit the jar on to melt the wax and pour into this jar.
All this wax can then be melted down by placing the jar in a pot and filling the pot part way with water, so that the water comes up the sides of the jar. Allow wax to melt. Then use a long plastic knife or spoon to stir the wax and blend scents and colors. You can purchase wax colors to even out the colors, especially if you have a lot of varied colors. When I made mine, I just left them as is because at the time I was making a banana bread scent, and they came out a dusty mauve color.
Once the wax is melted, add extra scent, if needed. This is in the candle supply aisle of your local craft store. Blend well.
Using tongs or a canning jar tongs, lift the jar out and then pour the wax into a regular-size muffin tin or mold. This is my old, grungy muffin tin that I use for crafts. Fill about 1/4 to 1/2 inch full. Allow to cool completely. Once set, place the mold in the freezer for a few minutes, remove the tin, and invert the muffin tin over a plate. The tarts should pop out.
Voila! These fit perfectly into the bowl of most wax warmers.
Store these in a zippered bag or other closed container. Now you can design your own homemade tarts, with the scents you like best, and reuse your old candles and wax.