Select an adhesive remover specified for use on your type of adhesive. There are removers for tile mastics, vinyl tile glue, carpet glue and other adhesives.
Pull up the old carpet or hardwood floors. If you are removing adhesive from vinyl tiles and the tiles will not come up, use a carpenter's knife to cut the tiles into 2-inch squares so the adhesive remover can reach the glue.
Pour the adhesive remover onto the flooring adhesive. Spread it over the glue with a mop. If you are removing ceramic tile mastic adhesive, spread it with a stiff-bristled brush.
Let the adhesive sit according to the directions on the package, which will vary with the type of adhesive remover and the type of floor glue. The set time will be anywhere from 10 minutes to 2 hours.
Scrape up the softened glue with a floor scraper. Rinse the area with clean water and dry it with clean towels.