Some chav has graffitied my garage wall using a paint stripper or acid I think. I'm guessing, but it isn't spray paint. The white emulsion on the smooth rendering seems to have been eaten away.
I have re-emulsioned the wall several times and after a week or two the stripper/acid seems to eat through the new paint again. I need to neutralise the stripper/acid (and also the chav who did the damage.)
I would suggest several washes down with sugar soap and water before you paint. Now you have already painted the wall it may require some sanding to break through the paint surface before you wash down.
Best of luck can take ages to neutralise paint stripper.
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