How would flushing help? All you'll do is wash out any nutrients in the soil, and if you don't have any nutes in the water you use you'll just cause other problems. I believe it's called hypotonic stress? Or osmotic stress? Definitely osmotic stress. I usually don't bother with ph as I grow in soil, but do you have any info on the general ph of your rootzone?
Pruning the dead growth is fine, but I would hold off on pruning the yellowish stuff until you have new green growth. The parts of the leaves that are still green are still performing photosynthesis and feeding your plant.