Stucco, a type of exterior plaster finish, contains a weatherproof coating that protects the cement finish from the elements as well as termites and fungus. The material is also fireproof and doesn't need painting like wood and other exterior finishes. But stucco is not immune to dirt and stains, including residue from eggs. It is possible to remove egg stains and residue from stucco, but it is important to act quickly and not let the material dry and penetrate the cement finish.
Using a Detergent Solution
Use a water hose connected to a sprayer, pressure washer or power sprayer to spray the egg residue on the stucco. Spray from the bottom of the stain to the top to keep the water from pushing the egg farther into the stucco. Wear work gloves to keep your hands dry. If using a pressure washer or power sprayer, set the washer/sprayer to a medium setting between 2,000 to 3,000 PSI.
Mix in a bucket a cup of nonbleach formula laundry detergent and a gallon of hot water. Stir the detergent solution with a scrub brush. Apply the solution to the egg residue and scrub vigorously to remove the stain.
Spray the stucco from the bottom of the area to the top to remove the detergent solution and any remaining egg residue. Repeat this step until the stucco is clean. If fragments of the egg residue are still present, complete the steps in the "Using a Poultice Solution" section.
Using a Poultice Solution
Mix in a bucket a cup of nonbleach formula laundry detergent, a cup of talc, powdered silica or bentonite and a gallon of hot water. Stir the poultice solution with an old spoon into a thick paste. You can find talc, powdered silica and bentonite at your area hardware and home improvement store as well as online.
Use a trowel to apply the poultice solution to any remaining egg residue on your home's stucco. The poultice solution needs to completely cover the egg residue and any surrounding stains.
Cover the poultice solution with plastic wrap and let the solution sit for one hour. The solution breaks down the egg residue and stains.
Remove the plastic wrap and spray the stucco with water from a water hose, pressure washer or power sprayer. Spray the area from the bottom of the solution to the top until the stucco is clean and free of the poultice solution and any remaining egg residue.