Vinegar or baking soda: These natural cleaners work well to clean cement patios with stubborn charcoal or rust spots. Mix equal parts vinegar and water, scrub the patio with the mixture, then give it a good rinse. If stains don't dissolve, try undiluted vinegar.
Blackening of the surface is common when the concrete is “burned by late and vigorous troweling”. The more the troweling effort, the more compacted and dense the concrete surface becomes. The result is a reduction in the moisture content (water cement ratio) at the surface.
Green or black algae, mold and mildew, lichen, and moss can all grow on your outdoor concrete surfaces. These ugly growths spoil the appearance of your concrete, and some growths can even cause damage.
Alkaline concrete cleaners have powerful degreasing capabilities. They work best on petroleum-based stains such as oil, grease, soot, and tar. Our top pick for an alkaline concrete cleaner, Sunnyside 64216 TSP All Purpose Cleaner, is recommended for indoor surfaces and works quickly to remove tough stains.
Vinegar is an all-natural solution for cleaning concrete. It kills mildew and mold, removes grime, and helps treat set-in stains.
Experts say they can do the trick for the patio as well. 'You can remove black spots easily from patios in an eco-friendly, low-cost way, with white vinegar,' says Laura Harnett, Founder, Seep. 'It has antifungal and antibacterial properties and will also stop the mould or lichen growing back.
Cleaning concrete with muriatic acid can be a highly effective solution if used correctly, providing ultra-bright white concrete and removal of many types of stains. In one application, you can remove rust stains, oil stains, algae, and paint splatter with a quick chemical application followed by pressure washing.
As a gentler cleaner, bleach can't harm concrete's durable material. Aside from being an effective cleaner and stain remover, it also acts as a disinfectant to the concrete surface.
Putting a paste of powdered laundry detergent and water on the stain, says BobVila.com. After letting it sit, scrub it with a broom or brush and rinse the spot off with water. Scrubbing the stain with a grease-cutting dish detergent and a stiff broom, according to BobVila.com.
Sweep off or vacuum up any loose dirt, dust, and debris from the concrete surface. Using a garden hose, wet the concrete. Then, apply a mixture of trisodium phosphate and water, scrubbing the solution onto the surface using a stiff-bristled broom. You can also use a pressure washer for this step.
Excess Water
As the water evaporates to the surface and soaks into the cement that is an ingredient of concrete, it leaves behind darker spots where the cement contains more moisture. These will fade over time as the water eventually soaks into or evaporates out of the slab.
While it is designed to last for years after the initial application, the concrete can be made white again with diligence and the proper materials. Bleach is commonly used to whiten concrete and is very effective at doing so if the initial stain is removed beforehand.
Discoloration in later life can result from atmospheric or organic coloring; the concrete is just dirty. This type of discoloration is usually removed by high-pressure washing with high-pressure water and, if necessary, chemical cleaning agents. The use of calcium chloride on concrete can discolor the surface.
In fact, vinegar removes mold from concrete better than bleach. Bleach will only remove the top layer of mold, causing the mold to return.
Dish soap and water: Dish soap is a degreaser, and it works well to clean oily and grimy concrete. Create a cleaning solution of warm water and few drops of dish soap and apply it to the surface. Let it sit for a while, then mop the patio and rinse it with fresh water. Repeat the process as many times as needed.
Vinegar does not dissolve concrete itself but can degrade the cement that binds concrete together. As a weak, dilute acid, vinegar will cause only minor damage to concrete but can take the shine off polished surfaces. It can, however, be used to remove small amounts of cement from tools.
Combine 1 teaspoon of hydrogen peroxide and 1 teaspoon of milk in a glass bowl. Dip cotton pad or Q-tip in the bowl and apply to dark spots. Leave on for 15 minutes. Rinse with lukewarm water and finish off with your favorite serum and moisturizer.
Vinegar should only be used for 30 minutes on polished concrete. Leaving it for an extended time will kill algae and damage the cement in the concrete. But for unfinished cement, you can surely use vinegar for an extended period. It is safe and will be the most efficient cleaning agent to remove algae.
Despite the signal word danger on most such labels, gardeners may instead just see vinegar and be careless. Sobering details: In concentrations over 11%, acetic acid can burn skin and cause eye damage, and concentrations of 20% and above are corrosive to tin, aluminum, iron, and concrete and can even cause blindness.
Some of the most effective household cleaners aren't meant to be mixed. You probably already know never to combine harsh chemicals like bleach and ammonia (or really, bleach and anything). But common pantry essentials that are often used for cleaning — like baking soda and vinegar — shouldn't be mixed either.