As far as the Conk go's... (if that's what it is)
The trauma layer can be removed and used as a slightly lesser alternative to Amadou ~ from the Horse Hoof Fungus.
It also makes an excellent ember extender for bow/hand drill and can sometimes be referred to as 'the bushmans stove'
If its Artists, it should be white underneath, and go brown to the touch from the oil on your fingers. Artists used to scribe on the white flesh, hence the name.
They are very slow growing, so I've only taken one.