Sweep the surface of the concrete with a stiff-bristled broom to remove any loose debris and dirt covering any of the carpet glue present.
Scrape up as much of the glue as possible with a floor scraper. Place the scraper at the edge of a glue patch and work the front edge under the lip of the glue. Push forward along the concrete to loosen the glue and to pry it up from the concrete. Pull the glue away in strips by hand.
Cover the remaining glue that you were unable to scrape away with a layer of soy-based mastic and adhesive remover. Brush the remover into place with a paintbrush and allow it to sit for 30 minutes in order to penetrate to the base of the glue and break its bond with the concrete.
Scrape the loosened glue off the concrete with the floor scraper using the same process as in the first scraping.
Wash off the surface of the concrete with clean water to remove the mastic and adhesive remover. Allow the concrete to dry, and then examine the surface for any glue not removed with the second scraping.
Cover any glue left on the aggregate concrete surface with another layer of mastic and adhesive remover. Wait 30 minutes, and then wipe the glue patch off the surface with a rag. This enables you to get any glue that’s seeped into the small voids between the aggregate of the concrete.
Wash the surface again with water to remove any remover residue left in place.