Very easy method in Acrobat:
http://zengrain.com/how-to-remove-go...-domain-scans/
- From the buttons on the right side of the main Acrobat window, open "Print Production > Preflight"
- Select the Profiles tab (I've also selected "Acrobat Pro DC 2015 Profiles" from the topmost dropdown)
- In the list of profiles, find "Create PDF layers > Put all transparent objects on layers" and double click the profile
- After it's done, close the Preflight window, and open "Layers" (button on the left side of the main Acrobat window)
- All the Google watermarks are now in their own layer - click the eye icon next to it in order to hide them all
Three alternatives to finish removal:
- Right click the layer and open its' properties, set the "Default state" to "Off", then save the file (seemingly easiest and fastest)
Or:
- From the "Options" dropdown menu button (right above the list of layers), select "Flatten Layers", then save the file
Or:
- From the Preflight window, find and double click "PDF fixups > Flatten transparency (high resolution)" - this alternative might sometimes result in better filesizes (just as often as not)