Answer:
Devin's problem can be solved by exploiting the activity series of metals.
Explanation:
This determines what metals are more reactive and would be readily displaced in a reaction.
Seeing as they are both metals scraps of similar sizes, filtration isn't a solution. But since Copper is lower on the activity series than Aluminium, adding an acidic solution (say tetraoxosulphate VI solution) to the mixture, would have aluminium in solution and Cu as residue which can then be filtered off.
I hope this was helpful.