Can I use aluminium containers to transport ESD sensitive PCBs?
Conductive bins are just fine for transporting ESD sensitive boards. Any protective packing in the bin to avoid mechanical damage to the boards must be conductive, for instance conductive foam. The ground conductor(s) of the board should be in electrical contact with the bin.

You must also make sure you load and unload the bins correctly. Do not touch the boards in the bin without taking the same precautions as for loading and unloading.

When you load a bin, the board and the bin must be at the same potential. This means electrically connecting the bin to the board or board handling kit before, and during, the transfer. This is perhaps most easily done by putting the bin on your anti-static workstation mat, or briefly connecting a ground lead to it. 

The same goes for unloading a bin. The bin must be at the same potential as the surface or kit that is to receive the board.

Once the bin is loaded, it can be disconnected from ground, and freely taken to any potential.