The logo in the second images shows that it has also been debarked



This pallet is about as clean as they get. It was heat treated, produced in the U.S. and debarked.



There are some additional codes that can go on pallets but the main one to watch out for is MB. It means it was treated with Methyl Bromide.



If you don't see an IPPC logo then you know not to use it. While a pallet may be perfectly safe without the logo, it could also mean it was treated with chemicals.



Another issue is what has spilled on the pallet. I'd be careful, personally, about oily pallets or ones that have clearly had something spilled on them.