Magnets and pickups need to be handled with extreme care and should be kept a safe distance apart. I would keep pickups approximately 3-4 inches apart. Magnets can be altered by the placement of other magnets or pickups in close proximity to them. I see pickups displayed in stores stacked on top of each other or on top of instructional video tapes. This improper way of displaying can alter the pickups efficiency, especially when being shipped as they are packed usually on top of each other and move back and forth in a box.

The movement of two magnets next to each other can diminish the alignment of the domains within the magnet and can cause the pickup to work improperly. Never stack pickups next to each other for long periods of time. Stronger magnets can realign the magnetic domains in weaker ones which can alter the tone and output of a pickup.