Thank you Sall!
I have begun the weathering with pastels and ink.
I used Tamiya pastels for the locations where the pilot and mechanics manipulate the aircraft. Not really visible on the photos, but well on the kit
The ink: Citadel Colors Brown Ink. Used for the "pissing oil"... Some photos show that the Fokker D.VII was a big oil consumer, and that oil pissed on the fuselage. I applied drops of ink, than I used Q-tip to expend the oil... I like the final result, that gives life to that aircraft.
Weathering to be continued...
I have also placed the exhaust pipe and the machineguns.