> "K2pdfopt works by converting each page of the PDF/DJVU file to a bitmap and then scanning the bitmap for viewable areas (rectangular regions) and cutting and cropping these regions and assembling them into multiple smaller pages without excess margins so that the viewing region is maximized. Making use of this method, k2pdfopt can re-flow text lines, even on scanned documents"

Looks promising. Hopefully this would also remove javascript and executable code from the source PDF, although any exploits may run within the context of the converter. To be safe, conversion could be run from a livecd.