Chaga? You mean tinder fungus?
Go for a walk in the woods. Find a birch tree. Any big lump sticking out on the side of the birch tree that looks like burnt charcoal is chaga. Remove it from the tree and bust it up. Works great in fire pistons and with flint and steel… I keep some in an airtight metal tin, along with some charcloth, a hunk of flint and a fire steel.
The wicked flee when none pursueth..." - Proverbs 28:1