Hey Madrobot,
I've had good luck aging a similar crate (to display my Grail); I did some random gouges with a large flat-head screwdriver, flattened out the corners/edges with a hammer, then beat the crap out of it on my gravel driveway to the great amusement of my mailman - basically scraping each side against the gravel, leaning into each side and twisting it into the gravel until it looked "well traveled". I then made a batch of strong instant coffee and applied it with a foam brush, saturating a side and then immediately wiping it off with a rag until I'd finished the crate inside & out. I repeated this on the outside so the inside would look aged but less so and "protected" from the hazards of temple raiding...
I similarly aged the raffia the grail's packed in (though I used a very large sponge and applied it to the raffia in a trash bag - it's effective but very messy) .
...And I've gotta heap some more praise onto you - that fossil hand is phenomenal!!! :eek
Take care,
Mike