How to truly crop a PDF file

The Crop tool in Adobe Acrobat is non-destructive; this means, once you've made a selection and you're then shown your cropped area, the PDF will still retain all the other canvas data and elements. This can cause issues later on, so if you're after a true crop of an area within your PDF, this is how to do it...

Step 1
Make your crop, as usual, using the Crop tool.

Step 2
Now this is the part that makes all the difference: export the cropped PDF as a Postscript file.

Step 3
Close Acrobat. Double-click and open the Postscript file. A window will appear, which processes the PS file and generates a new PDF file. This new PDF file is now a true crop.

Thanks to those in the following discussion:
http://forums.adobe.com/thread/471138