How do I flush the sand out from the frame from media blasting?
 

Picked up my bike from the powder coater today and noticed there is a lot of the media from the blasting collected on the inside of the frame and i'd liked to flush it out before installing the bottom bracket. It seems like there's some grease also, so I'm assuming I'd need to use some sort of solvent.

Is degreaser followed by water a horrible idea? What could I use that won't damage/weaken the powder coat, and won't leave rust in my frame.