Simple take a can (beer is best

Using just a basic soft drinks can, I can normally get around 3 hours of use out of one of these, thats around 5 tablespoons of veg oil.
The advatange they have over candles is the fuel is self contained so no mess. Also since only the wick is ever alight, the oil researve never gets hot, so you can happily carry one of these round in your hand at the base, with nothing more than a mild warmth. In addition you can knock one of these up in about 10 minutes start to lit, compared to the time to melt and form candles.
Granted not all of us will use drinks cans, but there are plenty of other folk out there who do, it's not hard to get a sackful, and any leftover bits of tin can always go back into the recycle bin afterwards.
Next on my agenda is to knock up a small wooden base holder for them with a handle for easier and safer carriage.