The Nikasil cylinders will only be magnetic on the inside (bore) of the cylinder.
The high nickel plating is what will show attraction to the magnet.
The aluminum casting will not be magnet on Nikasil, Alusil or Silimal.
If the bore shows any sign of magnetic attraction it is Nikasil.
As for mixing up Alusil cylinders it really doesn't matter if you're throwing them in the trash.
