Before 5 october you can go to Gålö (close to Dalarö) and look at a charcoal kiln (kolmila in swedish). It is a burning stack of wood on low intensity that is making charcoal. They use sand on the outside of it to keep it burning for a long time.
A visit to Gålö is well worth it, but you have to hurry. They also have charcoalbuns, that is like a pankake baked on charcoal.
It is for use a nice outing and I strongly recommend it!