If you forgive my english as well I can try to help you. When Karl-johan gets older the pore (the green stuff) can be very “spongey”. Make sure that you only use the one that feels hard and not “spongey” in raw shape. If the pore are to soft just take it of and make sure that the rest of your mushroom are fresh and not colonized with fly larva.
If the “hatmeat” are soft as well just leave it in the forrest. Sometimes it´s only the feet thats hard enough to use.

Most of the times (at least in my forrest) it´s only the smaller one that are good enough but if the weather are dry and no insekts have found the big one you can be lucky.

I hope my answer could help you untill somebody else can give you a better answer.

Thank you so much, Madde! That’s exactly what I needed to know. We will probably leave those huge karljohan’s in the forest from now on ;)
I appreciate your help answering me in English, very much! I am just beginning to learn Swedish :)
Thank you again!

Barbara, all edible fungi have a best-before date, and your Bolete had clearly passed it. The pore layer gets olive-yellow from the spores that are olive-brown when mature, that in itself is not a sign of deterioration, but deterioration is expected to follow soon after maturity. Stick to the young ones!

Haha, thank you Karl, that is great advice I will take!! :)