Well, our weaponry and stuff abandoned in Afghanistan were seen on Ebay. They could check there.
Talk about a gun buy back!
Not much artillery ammo in Afghanistan.
Lots of 5.56 and 7.62, but there is no small arms ammo shortage in Ukraine AFAIK.
And MRAPS. Which it turns out the Ukes have decided are very useful. They are very resistant to artillery near-misses, unlike, say, BMPs and BTRs. So you could try to get those back.