The best way to remove texture is not to scan, but to photograph the photo with a camera, lit so that the texture doesn't show. This is the second best way and is a very valuable tool in saving detail that would otherwise be lost forever (I have not yet been able to do a retouch that was as good as not seeing the haze in the first place, which photographing or this method of scanning accomplish).
Credit and thanks for this idea goes to Stephen M.
Here is a before and after detail of the sample photo;
Here is how to do it;
First scan your photo then without changing any scanner settings turn your photo upside down (around 180 degrees) and scan it again. You should have two scans that look like this:
So now flip the upside down scan (Image > Rotate Canvas > 180 degrees).
Select the move tool (shortcut v key).
Drag the background layer from one image onto the other image.
Change the top layer to difference mode, it should look something like this
Your layers palette should look like this (minus the levels layer I added when I was doing it)
Be sure that the move tool is still the active tool, and the top layer with an image is still the active layer. Drag the image until you see them register, remember that there will be a little detail showing no matter what because of the differences in the scanner light reflections. So just pay attention to the detail that is in both photos.
If the photo registers in the middle but not in the corners you will need to rotate the top image. To do so you will need to Transform the top layer. Seclect Edit > Free Transform (shortcut control/command T). To rotate with the mouse go outside of a corner until the mouse becomes curve with arrows on it and drag, or enter a different number here
Note: You can also use your up and down keyboard arrows once your curser is in this angle opening. Once rotated hit enter on your keyboard to save the transformation.
Once you get the two images registered, change the top image blend mode to darken.
That is it, you are done. Adjust and retouch with a smile :)
Why it works
The scanners light is one side of the scanners 'lens', so each bump has a reflection on one side and not the other. The second scan sees the reflection on the oposite side. Darken blending mode uses the top image where it is darker than the bottom image, thus removing most of the reflections.