Now its time to prepare to extract! At your fire site dig a small whole in the ground and insert another small metal container, i find a baked bean can is best, then fill in the gaps around the can with earth.

The whole in the large tin needs to go directly above this can. Make sure the rim of the baked bean can and the base of the tin are flush together. You can move more earth up and around the sides of your large tin to prevent it from moving out of alignment.

 
Now light a fire on top of the tin. When the bark inside the tin is heated to extreme temperatures it releases the tar as a thick vapour. This vapour will go down through the whole and distil in the baked bean can underneath. The process takes a few hours for all of the tar to extract properly. For this time you should keep the fire well maintained.

After a few hours have passed and the fire has nearly burnt out, all that will be left in the tin will be the charred bark. Lift the tin off to reveal the tar in the baked bean can. My tin full of bark typically collects just a little less than half a can of tar.
Note: Do not remove the tin from its position while the fire is still burning around it as the vapours are very flammable and catch alight easily.

 
The tar will be very runny at this stage and is good to use as a preservative for wood and I've heard it has several medicinal properties. If you want to make your tar into glue then keep on reading...