The lady makes soap, and some customers who say words like "detox" request soap with activated charcoal. She gets hers from a soapmaker's supply called BrambleBerry. But says you can get the capsules at WalMart or any health food/ organic / co-op type store and open em up for small quantities.
I use it mixed with sodium silicilate (waterglass) as an alternative to furnace cement when I think there is serious spider webbing or other signs of carbonization that has invaded the wood. I only apply this mixture to the spot in question and a minimal amount of the surrounding area. I used furnace cement for years, but it is harder for me to work with. For lesser issues, or just to assist with break in if you tend to have spider webbing, you can mix it with maple syrup, honey, grape jelly, or plain yogurt to coat a bowl with, up to and including the whole bowl.
And I do not know the difference between activated and non activated charcoal. There was a thread here that discussed charcoal as being superior to cigar ash for making pipe mud, but I don't recall if it distinguished between the two types of charcoal.