The method you use to cover your scribble area depends on the type of surface covered with graffiti. Different surfaces must be treated differently.
For example, wood surfaces can be treated with several primers and layers of ordinary paint. It may take a few layers longer than you expect to cover graffiti completely.
You need to plan the drying time between each layer. Have a peek at this website to get graffiti removal services.
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If you are coating metal, you can try other paint removers available in the market. Depending on the type of paint the artist used to create the graffiti, you may need to try more than one brand.
If you find yourself on a metal surface doing post-processing work, pay attention to the tape you use. Otherwise, steel wool can be very useful for removing scratches.
For brick or cement
You can use paint remover on brick or cement surfaces, but you need to make sure it has extra strength. You will also need to use a wire brush to blend the area.
After abrasion, rinse the area with a hose. You may have to do this task several times before you can erase your sketch. You can hire a graffiti removal specialist by searching on the internet.