You can straighten push rods. I BROKE several rocker arms. Best thing I have done was to use wd40 and a tiny little brush and scrub the valves as good as you can, keep turning over the engine and scrubbing and spraying and tapping the valves softly with a hammer all the while. Its a pretty long process but it was easier then pulling the head which I might have done if I had easier access, the coe does NOT have good access! I also flushed the engine with a few gallons of diesel before running it.
Jeff