First, I cleaned the countertop well with warm soapy water
Clean and dry
240-grit sandpaper
I sanded VERY carefully, especially at the routered edges
Just testing this approach on one part of the countertop, just in case
Detail (not that you can see much besides dust and grain)
Cleaned up the dust...
... with odorless mineral spirits
After the Waterlox sealer has been applied
Up close
