To remove paint on brick, use a good paint stripper if it’s a smooth surface. Paint on brick can be hidden with brick-colored flat primer paint. Don’t use muriatic acid, paint thinner or smear it.
The method of removing paint from brick depends on the porosity of the brick. Drips of paint on brick are sometimes there for years, I’m sure.
The rougher the surface the more difficult stripping the paint will be. If the brick is smooth, a paint stripper will possibly work fine. If it is rough, it will take several coats of a good stripper. Time and patience will be important here.
Be careful not to smear the melting paint, a large, faded light spot is more noticeable than a small bright spot. A stripper that is water-soluble will be easier to clean off with a scrub brush and water.
If the stripper isn’t working, we use an alternate method of hiding the paint. One trick used with red brick is to cover the paint spots with a red primer. The primer is dull with no shine so it does a great job of camouflaging paint with an acceptable color. It may not be perfect, but it is much less noticeable than the paint spots. Of course this idea and color isn’t for every house, only the darker red brick color works here.
Your brick may require a custom color in order to match. Most stores can match the color close enough to hide the paint spots, just make sure it is with a flat sheen, glossy paint is quite noticeable.
Some tricks not to use:
Do not use muriatic acid thinking it will strip paint. It will only clean it.
Paint thinner will not soften or remove dried paint either. It is best used to clean off wet or non-cured paint; not paint cured over five days.