Pix added: Best way to clean up valve seats & a couple other questions

[700rpm]

I pulled the head on my coupe and there was a moderate amount of carbon, the worst on pistons #3 & #4 (see photos). When I removed the valves a couple of the seats were black, especially #5. What it is the best way to prepare them for grinding and seating new valves?

Also, looking at the photos, what do they tell you about what the engine was doing to create these conditions?

BTW, there was one Ford script valve, one marked EX, and one marked R.