Pick up blueberries off the concrete surface with a paper towel. Discard them in the trash.
Pour 1/2 cup of 12 percent hydrogen peroxide into a bucket. Add 5 drops of ammonia. Stir the solution with a paint stirrer.
Put on rubber gloves to protect your hands from the ammonia solution. Wet a scrub brush with the peroxide and ammonia solution.
Scrub the concrete surface to remove the blueberry stains. Rinse the scrub brush as needed. Wet the brush with the solution and continue to scrub.
Sprinkle white flour over the concrete to cover the blueberry stains. Allow the flour to soak up the ammonia solution before drying on the surface.
Remove the dried paste from the concrete with the scrub brush. Pour water over the concrete to rinse it. Allow the concrete to air-dry.