In article ,
says...
wrote:

So, as a last resort I tried to burn it!.. I tried using petrol and it
just flames, but very little damage appears to be done to the wood.. I
then tryed BBQ lighter fluid and that seemed to work better. However,
the BBQ fluid has run out and I am back to petrol again.

Home made napalm? Polystyrene dissovled in petrol to form a paste like goo?

The problem with adding anything combustible is that it will burn, not
the wood which is underneath and starved of oxygen. Add an oxidant and
the wood will burn.