I checked the frets to make sure they were all level. There was one or two that needed attention but no big issues.
I checked by letting my tiny square straddle three frets at a time. A high fret will cause the square to rock.
Then I taped the fretboard and made sure all were crowned properly and polished them.
After cleaning the fretboard thoroughly with some naphta and scrapers I oiled it with linseed oil and restrung it. It barks as it should, one size löuder!