See also:

Removing spots
Remove tar and oil spots, industrial dust, insects, and tree sap as quickly as possible from the surface of the paint to avoid lasting damage or staining. Special cleaning products are available ...

Troubleshooting guide
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Glass
When cleaning the rear window, it may be easier to clean if the high-mounted stop light (if so equipped) is removed first. Be careful when removing the high-mounted stop light to reduce the risk ...