Here's how to make a very simple little fat-burning lamp that is specially designed to be used with fuels that are solid at normal room temperatures, such as the leftover fats from cooking bacon, sausages, duck, lamb, etc.
The reason it is able to do this is that surrounding the wick, there are protrusions in the shape of petals - these capture some of the heat from the flame, which is then conducted down through the body of the lamp and dispersed through the feet, heating the fat reservoir and keeping it liquid and able to flow up the wick.
It's made by Lost Wax Casting using everyday materials - this method is quite easy and can be used to make a wide range of other small metal objects.
In brief, Lost Wax Casting consists of:
Making a wax model of the object you want
Encasing the wax model in something heatproof such as clay or plaster
Melting out the wax
Pouring molten metal into the space left by the wax
Removing the mould material and tidying up the finished object