Sweep the porch to remove dust, dirt and loose glue particles.
Mop the porch with hot water to help loosen the glue.
Use a scraper to remove as much of the glue as you can lift without damaging the concrete.
Apply a commercial chemical adhesive remover to the remaining glue spots. Let the adhesive remover sit for the time specified by the adhesive remover manufacturer, then scrape the glue from the concrete.
Sand any remaining spots of glue with a medium-grit sandpaper.
Pour 1/2 cup dishwashing liquid into a gallon bucket. Fill the remainder of the bucket with cool water.
Mop the porch with the dishwashing liquid and rinse it with cool water. Make sure you remove all adhesive remover and soap from the concrete.