Antique Wooden/Copper Barrel Mug Waterproofing

I recently picked up a hand-made wooden barrel mug with copper straps. It's in nice condition, except for the fact that it leaks. It feels like the inside was sealed with some type of wax, but some of it has worn away. Anyone know a way of sealing the inside of the mug to make it usable again? I'm attaching a couple of pictures.

Thanks.

IMG_2949.JPGIMG_2950.JPG

Attached Images

• IMG_2949.JPG (141.8 KB)


• IMG_2950.JPG (132.7 KB)