To make sure your graphics always look their best, follow the manufacturers' maintenance recommendations exactly. These will be things like washing the graphics regularly with non-abrasive detergent and purchasing the tar and bug remover that the manufacturer suggests.
Keep in mind that the longer gunk is allowed to remain on your graphics, the more difficult it will be to remove down the line. And, you must clean off fuel spills ASAP, because this can degrade the vinyl adhesive of which most fleet vehicle visuals are composed. If the nature of your work necessitates that automated washing is used to clean off your vehicles, make sure you go with touchless. That’s because brushes can severely damage your graphics.
If you’re pressure washing your vehicles, make sure you keep the pressure below 200 psi. Also, the temperature should be below 180°F. Soften gunky foreign matter like insect residue by dousing with hot soapy water and letting it soak in before rinsing off.