A recent xkcd contains the claim that honey has a shelf life that's so long that edible jars of honey have been found in Egyptian tombs several thousand years old.
Image taken from http://www.xkcd.com/1717/, licensed under a CC BY-NC 2.5 license.
The Smithsonian article in question appears to be The Science Behind Honey’s Eternal Shelf Life, which starts off with
Modern archeologists, excavating ancient Egyptian tombs, have often found something unexpected amongst the tombs’ artifacts: pots of honey, thousands of years old, and yet still preserved. Through millennia, the archeologists discover, the food remains unspoiled, an unmistakable testament to the eternal shelf-life of honey.
The Smithsonian article references SL Buchman and B Repplier's Letters from the Hive, and I'm unable to get hold of a copy, but the claim is quite extraordinary to be citing a book of that sort.
A previous question on this site asked about the shelf-life of honey, but the answers there don't really address the thousand+ year timescale, even though the OP's source there also contains the claim that
You could place it anywhere for thousands of years and it will not spoil. In fact, edible honey was found in ancient Egyptian Pharaoh King Tut’s tomb!
Since xkcd has sort of left things hanging, I'd like for someone to take up Megan's track and show some more solid evidence either way for the claims of edible honey in Egyptian tombs. In particular, if the claim is true, then my feeling is that the must be credible reports in the archaeology literature, so those would be nice to see. (If it's false, on the other hand, then it may be harder to debunk.)