Iron pyrites and flint, together with birch bracket tinder. A stone age firelighting kit.
Here's some info about prep I found on the very exciting intraweb:
To make this tinder cut open the fungus, then using a knife remove the hard
top and lower pore tubes, leaving the fluffy, chamois leather like layer. Then
boil in a wood ash solution for 4 – 8 hours (some references say up to 24
hours). Other references I’ve read say that the fungus should be boiled in urine
for several days, a method I have not tried yet. When boiled the fungus softens
allowing it to be hammered flat. Tip, doesn’t need to be hammered too hard, best
to hammer the underside of the fungus, top falls to bits more easily. When dry
the tinder’s surface can be fluffed up with a knife allowing it to catch small
sparks produced by the traditional flint and steel (its spark catching abilities
can be enhanced by charring an edge, also read rubbing in charcoal dust helps).
Tip, best to scrap off a pile of fluffed up fungus instead of trying to light
the main piece. When lit smoulders very well, easily blown to a hot bright glow,
can be difficult to put out when lit.
Watching: The Evil That Men Do-Charlie Bronson
Listening to: Wardruna