Maybe a 2 or 3 inch wide
paint scraper, the one with a hooked type blade on a handle that you pull to scrape off
paint. I took up some old floor tile in my 1950's house that had some black adhesive holding it down. Lowes or Home Depot had some liquid remover for that stuff, but it was nasty messy and I finally just went with the
paint scraper. Best to use a respirator or dust mask because who knows what's in that adhesive. May be something that's now proven to be bad for us.