There are a few methods you can use to remove spray paint on concrete. For water-based paints, washing the area with soap and scrubber may work. For dried, oil-based paints, a chemical stripper may be needed. If you decide to use a chemical stripper, be sure to follow the instructions on the label and wear the appropriate safety gear. If you’re unable to get rid of the paint stains on your own, you can always seek the services of a professional graffiti removal company.Source :https://paintexplained.com/how-to-remove-spray-paint-on-concrete/
Vinegar
One of the best ways to clean concrete is by using vinegar as a paint remover. This is an affordable home remedy that works well if the spray paint stains are not too extensive. Before you start cleaning, make sure to protect yourself by wearing gloves, goggles, and a mask. This is because vinegar can contain chemicals that can affect your health.
Step 1: Fill two buckets with warm water. Add a bit of dish soap to the first bucket. Then, mix a solution of the vinegar and dish soap in the other bucket. Pour the mixture onto the concrete and scrub it with a brush. Make sure you scrub all of the affected areas thoroughly. After scrubbing, rinse the concrete with clean, warm water.
If the spray paint stain is still there, you can try using a paint thinner or spray graffiti remover on the concrete. These products can be a bit more expensive but are effective at breaking down and removing the paint. Be sure to read the instructions on the label on how to apply these products and how long to let them sit on the concrete.