One of my students needed a fretless for a musical production. I told him we could make one, since buying a new one was out of his budget. He brought in an $80 no-name “beater” bass.
I showed him how to make the tool he needed to pull frets without damaging the board. Then I demoed how to pull a few frets without damaging the fingerboard, and then handed him the tools. He pulled frets and I started filling the empty fret slots. 45 minutes later….
FYI, Goodfilla is the bomb for filling those fret slots.