stained

There is quite a heavy dirt level at the sides, at very lowest part of the car, almost under it. I can get everywhere to shine up lovely and gleaming, but near the bottom at the sill area on the outside, there is grime which I cannot shift no matter how hard I scrub! Any tips?

Noticed that there are brown rust coloured stains in the headlining driver side and under sun visor both sides, on the recently purchased 03 reg Leon 110se. Could this be from water penetration? Anyone had water penetrating the roof lining and how would it get in there? thanks in anticipation.