If you are unlucky enough to make some candles only to discover you have inserted the wrong wick, all is not lost. The following steps will enable you to replace the wick without having to completely re-pour the candles.
1. Get yourself an apple corer.
2. Push down around the wick, cutting the wax all the way to the bottom of the glass.
3. Gently twist and then lift to remove a 'slug' of wax and the wick. You may need to pull on the wick with some long-nose pliers. Retain the slug of wax, as you will use it later.
4+5. If the wick tab is still in the jar, remove it with a set of pliers.
6. This should leave with with a wick free candle. If your wax is not sticky, you may need to clean this hole out in order to insert adhesive, glue dot or a sticky foam pad.
7. Thread the new wick through the wax slug if it is still intact. If not, melt the wax you removed in stage 3.
8. Insert the wicked slug into the hole. If the slug was remelted, insert the wick and then pour in the melted wax.
9. Re-melt the surface of the wax to smooth out any bumps.
10. You have changed the wick without having to re-melt the entire candle. A real time saver :)