Pickup rewinding is the removal of existing or original magnet wire from the bobbin or coil form. If I need to rewind an old pickup, I first try to remove the original coil turn by turn to another spool till it is completely removed or to the internal break is found. Many single coils that just stop working can be due from a term that I’ve talked about many times called “ICPC” or inner coil pole corrosion. Inside the coil, oxidation can occur from moisture or other contaminants. The high moisture can cause the magnet rod to rust and eventually break down the magnet wire insulation causing the fine copper wire to break. This often occurs on Fender style pickups using covers that allow the poles to be exposed and moisture to penetrate the bobbin. The bobbin is made of vulcanized fibre (chemically treated and compressed paper) and can easily absorb moisture over long periods of time. By removing the coil turn by turn, you can rewind the pickup with the same magnet wire with a loss of only a few turns. This takes time and I’ve built automatic de-reelers to remove each turn of a coil from the bobbin. Vintage pickups are valuable, unique in tone and should be given a great amount of attention. If the coil is beyond repair or damaged by unskilled hands, then the pickup can be rewound with new or compatible magnet wire.