Firstly, dissolve as much as possible using Bare Brick Stone & Masonry Graffiti Remover (BBSM) as instructed.

Remember longer dwell times make a huge difference. Don’t be afraid to flood coat several times and leave the product on for an hour or more or even over night before rinsing the next day. If you have a hot water pressure washer this is the time to use it! Make sure its putting out steaming hot water before you start rinsing the wall.

Still, if a ‘graffiti shadow’ or stain persists follow the notes below.

If the graffiti was from inks, dyes, boot polish or ANY color spray paint with RED pigments in it (for example reds, browns, oranges, pinks, purples etc.) apply Feltpen Fadeout thickly and reapply if needed. You can also cover with black plastic so that it stays wetter longer. Once you see the stain begin to fade away it will disappear completely. Reapply until it appears that no more fading will occur. See “Working with Feltpen Fadeout” and Feltpen Fadeout TDS sheet for further instructions and illustrated examples.

For black and blue spray can paints that are threatening a shadow you should first apply several flood coats of BBSM, and consider a coat of Transgel on top, overnight. This will help keep it all wetter longer and dissolve graffiti more thoroughly. Only do this if it is safe from the general public. Consider wrapping a plastic sheeting, employ a guard if you have to.

In the morning, use very hot water with a pressure washer. You may have to use the gun quite close to the surface so as to avoid prolonged time in gunning in one spot only. Keep the tip moving very fast around, over, below and above the graffiti shadow.

On limestone it is not uncommon to see a residual shadow, even after extended dwell times with BBSM. This type of stain can be easily removed using a diluted muriatic solution.

Use 4 parts water ; 1 part Muriatic (stronger dilutions can be utilized. Wet surface down thoroughly before applying)

Brush on acidic solution, agitate with brush and rinse off with pressure washer.

Repeat as needed.

This technique will ultimately fix the problem and you should be left with a perfect looking wall like this example below.

Graffiti Removal from Limestone, courtesy of NYC Power Wash.

Please remember other people’s 'stuff ups’ can take a lot of time to fix. Don’t under quote or underestimate the job. Set an hourly rate and be sure to remove a small section first before quoting a large job so you can set expectations.

When removing shadows resulting from other removers being applied it can take many extra coats and longer dwell times to fully dissolve graffiti.