One thing that you can do to prepare for eventualities ranging from going camping to having a party is to make your own candles. The kits and books out there are fairly extensive on how to put almost any type of wax or fat together with steric acid, colors and fragrances to make a candle. That is not what I am talking about. I am talking about a candle that can provide light, heat, a cooking source, all sorts of things.
To start, you will need to gather things for the candles. This may take a while, unless you already have too much junk around. Start collecting cardboard, envelopes, newspapers and sawdust along with old candles, paraffin from canning jars and lard and other hard fats. Cans, the flatter ones for canned meat or cat food, should also be collected, but candles can be made in cardboard liquid cartons or frozen o.j. tubes. Almost any paper or metal container can be used to form a candle, metal being better for a survival style candle.
Unless you already make candles, you will need to invest in a few things. You will need a double boiler or nesting pans you do not want to use for food any longer. A lasagna pan or steam tray can be used on the stove to hold the water for a large version of a double boiler. Never try to melt wax in the oven or 'directly' on the stove without a double boiler. The wax could catch fire, which is not what you want at this point. If you do already have candle making equipment, make sure you have a pan just for this project, and you will find out why in a moment.
If you are using lard, like from meats you have cooked with, you should strain the fat through a cloth to get the big debris out of it. A cheap and disposable way to do this is to take a toilet paper roll and an old sock that is about to give way and use them as funnel and strainer. Make sure you have washed the sock beforehand. Melt the fat, pour it through the sock into the candle pot and throw the soaked sock away. Keep the toilet roll, if possible.
Add the wax that you have a small chunk at a time into the double boiler and melt. Do not boil the wax. Do not put a tight lid on the wax. Do not let the wax spill or splash. This may seem silly to say, being a scalding hot liquid, but special precautions should be used to keep yourself safe. You may need to put in a hardening agent, like steric acid. Consult a local craft store or hardware store for supplies and books.
Take the cans, cleaned out please, and set them on a heat resistant surface. If you know you are going to spill, put a split paper grocery bag on your surface. Tear up the cardboard, envelopes and other paper goods into strips about 1 inch wide. You will be putting these into the cans in coils. Try to have only two or three strips of cardboard or five or six strips of paper in the coil. This is the time to get a good number into the cans. What these are are the wicks for the wax that will be in the cans.
If you have sawdust, add it to the wax. For every gallon of liquid wax, put in up to a cup of sawdust. Some people say to put in as much as possible, but I am of the opinion that the sawdust, even though it is there to help with the consistent burn in the can, will cause sparks, smoke and possibly cake up at the bottom of the can in a useless lump. Not that I have had this happen or anything. What you need is a suspension of the wood particles, not a slurry. Add the sawdust a little at a time, constantly stirring until it looks like you have an even amount in the wax. This will not be suitable for things like tapers.
If you are using candle remnants that have coloring or scent, be careful adding any more. A little citronella is good to help keep bugs away, but add that to a collection of bayberry, honeysuckle, rose and other strong fragrances and it could be a little much. The scent that you smell as it is melted in the pan is close to what it will be in the canned candle. If you want the candle for food uses, do you want that scent/taste in your food? With the coloring, the more color the wax has, the hotter the temperature it will burn at. Mostly. I try to mix same colors together along with clean paraffin and oils to dilute the colors. You can get a good dark brown by mixing all of your colors together, though black can only be reached if you add real pigment.
Pour the wax carefully into the cans. Use the card board toilet paper roll to do so if necessary. Pour the wax over the 'wick' to make sure it gets soaked in the wax. After the candles have cooled for about an hour, carefully pull up part of the center wicking. It is easier to light it if you can get to it. After about 4 hours(yes, this is a long-term project), see if you need to put some more wax into the can. Wax as it cools shrinks, and as such leaves a gap or dip in the surface. Fill that gap and let cool for at least another 4 hours before you try to move the candles. It takes about 12 hours for wax to 'set' fully, but with the metal of the cans, it may take less time.
You should have some matches to put with the candle, a book of matches would be best. Take wax paper and rubber bands, if you do not have proper sealing lids, and make a lid over the candle and matches. Several layers may be needed, or also put the candle into a sealable plastic bag.
A way to use the canned candle for cooking is to have a small coffee can, cut a hole in the side large enough to get a sterno(tm) can or a canned candle in from the side, and a few vent holes cut into it around the top of the can. With the hole in the side, you can replace the candle when it has burned it's self out without having to reach into that hot metal. You can place the pot, kettle or gerry can you are using on the open hole and cook things on a reasonably stable surface. As I noted in passing, this would also work for sterno(jellied alcohol)cans.
When you need to use the candle for emergency purposes, or in place of sterno under a chafing dish, unwrap, place on a good heat resistant surface and light. Because of the home made nature of these, the burn time will vary, but I have had a good 4 hour standard burn on catfood can sized can candles.
For any candles made in cardboard tubes or cartons, please use a full sized coffee can with holes punched along the sides to burn it in. They become very hard to move once they are lit and the can will become a type of luminary, as well as a cooking device. As with the other canned candles, please make sure that you put the can on a heat resistant surface before you light the candle.
There are some really 'cool' ways of making candles, too.