Quoted from undrdog:No, I just want to get the brown stains off. The rest is fine.
It looks like it's bare wood in a lot of spots...are you repainting that? The stains on the yellow might come off with naphtha or alcohol and a little Magic Eraser (although I don't like the way those disintegrate into white dust).
I couldn't help it, but your comment made me think of this: