We use high quality adhesive to glue down wood floors in Santee CA, and it is very hard to get up! Glue down wood is scraped up in splinters. You cannot salvage boards for repairs. At Geneva Flooring, a flooring store San Diego, we have specialty machines that cut and scrape up glue down wood and tile floors. For wood, we make long cuts across the floor, every 3-5 inches, then scrape up the floor with scraper blades to get under the glue. It is manual labor, it takes time and experience to be effective, and the specialized equipment is expensive. Here is a video of the equipment cutting the floor and some demo pictures.