Spray paint/ graffiti on window

I got a new contract today, a KFC, approx 15 windows, $35 in out, monthly. Just a schedule filler really.

They have graffiti on one of the outside panes of glass. Its about a square foot. It has been there for “years” says the manager. I tried to scrape it but i was getting literally no where. It is really caked on, it could even possibly be glue (that the artist used). I told the owner theres a good chance it has corroded into the glass over the years of sun hitting it. All I had on me was Crystal Clear 550 for hard water, so I tried it, but no go.

Should I buy some commercial graffiti remover from the hardware store or would that be a waste of money? What are the chances it is irremovable? Homemade solutions?


Most aerosol graffiti removers contain xylene to dissolve the paint. Xylene is very volatile and can damage painted surfaces around the application area.

I carry a heat gun with me to soften the paint/vinyl/tint and then scrape it off.

Im only asking because you mentioned it looked like glue. Is it white?

Is it possible it’s that etching spray, If so I don’t believe there is a way to remove it. I would love to be corrected on that though.

Is it an acid-based type of damage?

Mechanical removal – such as GlassRenu – may be required.

Is it acid-etching? The best ways you can tell is if it is not cleaning off even with a scraper. It will also look like it has gone into the glass and usually you can run your finger through it and it will not feel anywhere near as smooth as the fresh glass surface down?

Anyway you can get a photo of the glass?