McFarland
My cleaning process:
1. Run 'Make map' with out grid lines.
2. Open bmp-file in GIMP and select the sea area by color and remove the sea.
4. Cut, paste and match the coast lines in groups when possible, other vise one by one...
5. Smooth the coast line / land seams a bit.
6. Set a new sea texture to another layer.
7. Merge the layers.
Works with micro 8*8 CB-map like mine.