nick wrote
Would there still be a benefit if I shielded it off but didnt then earth to it? Otherwise could you not use a screw or drawing pin ? to solder the wire to which in turn conducts through the foil ?
It has to have an earth otherwise it could even make things worse. A screw with a solder tag can work fine - just make sure it's not coated with a layer of plastic to stop it oxidising.
IME aluminium foil is usually more trouble than it's worth to use. One other problem with it is that if you have to use more than one piece, you then also have to join the two pieces together electrically. Aluminium can also change the sound of the pickups if it gets close enough to introduce eddy currents in the coils.
