Somewhere, a spy is being paid to go through Glenn Greenwald's trash.
I say the best way is to create lots and lots of false leads for them. Make a text file and type nothing but gibberish in it. Then print it out and send it through the mail. Do the same with barcodes. Go to one of those make-a-barcode websites and make a bunch of them. Put them together on a page, print them out and mail them. Fun for all! The agents will be forced to scan it, OCR it, then spend hours and hours trying to 'decode' your little gift. Go to a junk shop and buy an old Zip cartridge. I know I still have a box with about ten Zip cartridges in it somewhere. You don't even have to put anything on it. Just carry it through the airport. Then the agents will have to find a Zip drive somewhere to read what turns out to be nothing.
As far as the real data? Publish in on your blogger.com site. Nobody reads blogger sites.