Not everything I try works, but since you lot seem to like to read about failed experiments, here goes.
Paint the pagoda in rusty colours.
Slop a bit of wet salt on the surface.
Spray with a creamy colour - just a thin coat.
Look at wonderful building with rusty base and patched breaking through.
The salt wouldn't come off properly and stuck in lumps
The rusty colours didn't show through as I hoped
It looked rubbish.
Result - respray the model properly and attack with weathering powders.
Still, nothing ventured, nothing gained eh ?