From other Instructables, the candles that are made end up with small flames and reasonably random burn times. I wanted a commercial grade product that was "as good as new". So we decided to reuse those little aluminium tea lights.
Step 1: What you need...
1) x2 cheese wax shells
2) x1 used tea light container
3) 5cm / 2 inch of cotton string
4) Source of heat / pan or plastic bag to melt wax
5) Pliers / pincers & a blunt knife
First things first - remove the wick holder from the bottom of the tea-light. It's not glued in, just held down by the melted wax. Use the end of a butter knife to tease it out.