Crate markings....

hudson & allen might make some. i have some markings for teller mines and panzerfausts from them, along with some paper boxes, so i wouldnt be surprised if they make crate markings as well.

well the markings I go for stuff on my M10 from archer was quite hilarious.......

with a magnifying glass this is whats on one of the finer print items:

If you are trying to read what this says, you're proably spending too much time at your work bench.

the rest wre equally amusing.

I don't think there were any for crates and the like, though anyways.........

I use a Verlinden German Armor Markings stencil, which comes with a crate marking stencil as well.

I use Verlinden's US Army Dry Transfer markings.
http://www.verlinden-productions.com/vp_htm_0001_0600/0161.html
Most are so small that you can't read them with a magnifying glass, so they work well in any language. I have black and white set, but I don't know if the white is still available but you could probably get away with the US aircraft stencilling in white. If you use a pencil and only do a couple of swipes with the tip through the markings, they look old and worn, and because the lettering can't be read you can get away with that from the larger markings.