Please see the combined screenshot beneath; I see no CMYK values? I'm trying to fulfill step 4:
- Scroll to the page 22, as this is the first page with background fill you want to get rid of. Open again Tools → Output Preview and read CMYK value of the background. As I was converting Pantone with simulation to U.S. Web Coated (SWOP) v2, my CMYK values for background are 10:2:0:5. It's ok, if you will have different values. Just write them down as you will need to use them later.