How do you create water streaks?

[rickoshea52]

I'm looking for some advice here. I'd like to model the wet streaks created when water streams off from a rain channel and along the side of a flat sided diesel locomotive. I'm not looking to create the vertical streaks for a loco that has been parked for a while, it's the dynamic streaking you see left by water being blown from a rain strip and along and down in an arc.

I've thought about using Mig water effects blown with a straw or very low pressure air from an airbrush, empty of course.

Maybe you military modelling chaps have a secret technique to share?

Thanks.