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Spotting caused by external influences


Physical attack or discolouration of the paint surface due to various causes; the spots take on a range of shapes, colours and sizes.


  1. Tar – appearance: dirty, brown-black spots
  2. Industrial waste gas, for example, SO2 – appearance: large area or spot area turned matt (see entry on ‘Loss of Gloss’)
  3. Acid rain – appearance: no short-term visual effect, but can turn matt
  4. Acid (battery) – appearance: usually destroys the entire paint build down to the metal
  5. Tree sap – appearance: thread-like and droplet shaped, sometimes clear or brown-yellow marks with swelling
  6. Insects – appearance: marks of insect bodies visible in the paint surface
  7. Insect secretions – appearance: for example, bee droppings: long yellow-brown marks. Greenfly excrement: round, ring-like etchings
  8. Bird droppings – appearance: can vary depending on the type of bird, weather conditions and duration of contamination
Corrosion caused by battery acid, 5 x magnification
Discolouration from tar spots, 2 x magnification
Mark left by Fly remains, 25 x magnification
Corrosion caused by battery acid, 20 x magnification
Corrosion from Bird Droppings, 2 x magnification
Corosion from aphid excrement, 100 x magnification


Remove all foreign bodies and matter from the paintwork as soon as possible. Wash off tar and tree sap using Glasurit 541-5 Wax and Silicone Remover. Remove all other contamination with water. Regular paintwork aftercare is required (washing, polishing, wax protection, see entry on ‘Aftercare of vehicle paintwork’).


Depends on the extent of the damage. For damage to the topcoat, first, try to polish out the problem using Glasurit 562-1602 Fine Polishing Compound and finish with any standard high-gloss polish. As a second step, sand the area with P1200 and then polish with Glasurit 562-1602 Fine Polishing Compound and finish with any standard high-gloss polish. For major damage, sand down to a ‘sound’ substrate and repaint as necessary.