unlock PDFs using ghostscript. install gs from http://pages.uoregon.edu/koch/ before use.

unlockPDFs applescrapt

-- unlock PDFs with gs
-- licensed under public domain
-- copyright benjamin chodoroff 2013

-- where is ghostscript binary?
property gs : "/usr/local/bin/gs"

on run
  display dialog "drag n drop pdf unlocker"
end run

on open finder_objs
	repeat with i from 1 to the count of finder_objs
		set finder_obj to (item i of finder_objs)
		set the finder_obj_info to info for finder_obj
		if (alias of the finder_obj_info is false) and (the name extension of the finder_obj_info is "pdf") then
			set finder_obj_abs_path to the POSIX path of finder_obj
			do shell script gs & " -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile='" & finder_obj_abs_path & ".unlocked.pdf' -c .setpdfwrite -f " & finder_obj_abs_path
		end if
	end repeat
	display dialog "unlocked " & i & " PDFs"
end open