Scrape off loose adhesive with a floor scraper or putty knife
Apply a commercial adhesive remover suitable for concrete
Let the remover sit for the recommended time
Scrub the softened adhesive with a stiff brush
Scrape again to lift remaining residue
Repeat the process on stubborn spots
Use hot water and detergent to clean the surface
Sand or grind the concrete if adhesive remains
Vacuum or sweep up all debris
Wear gloves, eye protection, and a mask when working