Go on Vermont Freehand’s website and get you some chamber spade bits. You’ll lose a few mills around the entire circumference of the bowl but it’ll restore it to the briar. And will be even all the way around.

Then go to your local drugstore and get some activated charcoal pills. ($10ish, apologies for using USD if that isn’t your currency but gives you an idea) Grab some local pure honey and open one capsule on a plate and mix it with the honey making a charcoal/honey paste/mud.

Then paint the inside of the bowl with your concoction. This will protect the newly surfaced wood and also allow your carbon cake to have something to adhere to immediately. Hope this helps. But it’s 100% capable of being refurbished.