I had to build a new taller fence and so had to remove the old post from a MetPost – this is easier said than done.
First thing to do is to cut the wooden post off just above the Metpost.
I then had a go and drill some holes and setting fire to the wood – this is not a great idea as you need a lot of heat, you need to ensure nothing else is combustible around the area and you need to shroud the fire to keep it alight.
Then I tried a flat wood drill bit and drilled a lot of holes at all sorts of angles. This removes a lot of the material. I selected a 14mm diameter bit and a powerful mains drill.
Once you have lots of holes drilled vertically and at different angles you can then move the drill bit around and remove all of the wood.
The downside is this destroys the drill bit – a small price to pay as I easily removed 2 posts before damaging the drill bit and I could have reground it jjust for this type of work.