Wax looking stuff in oak barrel
I have an old 5L oak barrel that has been used in the past for aging rum. It hasn't been used in a long time so I am I the process of swelling the wood again by adding boiling water but when the barrel overflowed there was a wax like substance coming out.
Does anyone know what this is?
Second question, is boiling water enough to clean the barrel?
I am going to use I for flavoring cider.