Here are some tips for getting the most out of your candles and candle holders without a lot of fuss:
Save yourself the trouble by taking care of the problem straight away. As soon as you notice that the candle has burned down to a point that you won't burn it anymore, snuff the wick and allow the wax to become solid.
Place the holder in the freezer. Placing the cup/holder upside down is ideal.
After about 10-15 minutes you should be able to take the holder out, give the holder a little smack on the bottom with the palm of your hand and the candle should pop right out.
If it does not pop out and/or if you have waited a while before trying to take the wax out of your holder, take a wax scraper or a butter knife and begin to cut into the candle in a straight line. Before you have gotten halfway down, the candle should pop right out.
* Those rubbery washable butter knives they sell at the supermarket are ideal to use to protect your holder from nicks and scratches.
Good luck and happy burning!
I burn a lot of candles and I have found it much easier to remove wax from my candle holders with a little heat.
For NON-metallic candle holders; (I remove the metal wick holder from the bottom before burning the candle) I place these candleholders in the microwave for a few seconds to melt the wax out of them. Be sure to place a paper towel under them to absorb the melted wax. Usually after I have gotten most of the wax out I will heat it one more time and wipe it off with a papertowel.
For Metallic candleholders; I have a large glass dutch oven that I fill with water and put it on to boil. While waiting for it to get hot, I pick off as much wax as I can and place my candleholders into the water (gently as to not break them).
I try not to buy candle holders or sticks that have any plastic on them, I have not tried these methods on plastic. And I will also avoid candlesticks with glued on decorations, I don't know if pieces will fall off in the boiling water.
I've been recycling my wax and saving it to make more candles. I melt the old candle in the microwave (if in glass holders) for a minute or so. Then I dump the wax into a container for later use. I wipe the glass holder out with paper towels and they can be used again.