In many cases, debris is not readily visible, can be very easy to miss, and might not be removed with just a quick wipe. A soft, lint free cloth moistened with water is usually sufficient to clean debris but more stubborn debris might require additional steps.
To isolate the issue and properly clean the appropriate area, watch the video and/or follow the instructions below.

Step one: Determine whether the issue occurs when using the ADF glass or the flatbed glass
• Make a blank copy from the ADF and mark it "ADF."
• Make a blank copy from the flatbed scanner glass and mark it "flatbed."
-If the issue is visible on the copy marked "ADF," see Step two: Clean the ADF glass and white strip on the underside of the scanner lid.
-If the issue is only visible on the copy marked “flatbed,” use a soft, lint-free cloth moistened with water to clean the flatbed glass and lid backing.

NOTE: If needed, lens cleaner or nonabrasive glass cleaner can be applied to the cloth before cleaning the glass. Spray only onto the cloth and not directly onto the glass or device. Do not spray water or glass cleaner on the glass as it can seep under it and possibly damage the printer. Do not use abrasives, acetone, benzene, ethyl alcohol, or carbon tetrachloride on the glass; these can damage it and/or leave residue on the glass resulting in degraded copy/scan quality.

Step two: Clean the ADF glass and white strip on the underside of the scanner lid

NOTE: Dust might appear on the underside of the glass, but this cannot be cleaned and it has no effect on the copy or scan quality.

Open the scanner lid and locate the one-inch strip of glass to the left of the main scanner flatbed glass.
Use a soft, lint-free cloth moistened with water to clean the ADF glass. Some models use an upper ADF glass similar to the lower one. In this case, perform this cleaning step for both the lower and upper ADF glass.

NOTE: If needed, lens cleaner or nonabrasive glass cleaner can be applied to the cloth before cleaning the glass. Spray only onto the cloth and not directly onto the glass or device. Do not spray water or glass cleaner on the glass as it can seep under it and possibly damage the printer. Do not use abrasives, acetone, benzene, ethyl alcohol, or carbon tetrachloride on the glass; these can damage it and/or leave residue on the glass resulting in degraded copy/scan quality.

On the underside of the scanner lid above the strip of ADF glass, use a soft, lint-free cloth moistened with water to clean the upper white strip and metal strip (if applicable). In some cases, this is a glass strip similar to the ADF glass.

NOTE: Do not scrub or use paper-based wipes as this can scratch the surface.
If the white strip does not come clean, try again using isopropyl alcohol, and then wipe the surface thoroughly with a damp cloth to remove any residual alcohol.

Dry the ADF glass and upper strip with a soft, dry cloth to prevent spotting and then try again to copy or scan.

If the issue persists, see Step three: Isolate the location of the debris on the ADF glass.

Step three: Isolate the location of the debris on the ADF glass
Place a blank sheet of paper in the ADF and mark an “X” in the lower right corner as shown below.

https://support.hp.com/us-en/document/c06432233