Some audiophiles believe that cryogenic freezing of their audio equipment somehow improves the sound. New-age audio inventor and pseudo-scientist Peter Belt (of PWB Electronics) claimed that cryogenic freezing of CDs provides 'friendly', 'relaxing' energy patterns, making them sound better. However it is well known that cryogenic freezing of metal affects its crystalline structure and can improve its durability (as used in Dean Markley Blue Steel Strings and banjo tone rings). Although molecular structure may be altered it is quite another thing to say this change will have an audible effect.
The UK Chillertone company are selling cryogenically frozen guitar pickups and cables. They claim the metal parts of pickups and guitar cables undergo an ireversable realignment when subject to temperatures of -195 degrees Centigrade. They also claim that cryo-treated pickups will have enhanced clarity and sustain, and cables will also sound better. Lindy Fralin also offers a cryo treated pickup: the Callaham Cryogenic.
This freezing process might work: it should not be ruled out without proper evaluation. These claims would be very simple to test using basic electronic equipment and some liquid nitrogren (but there is no supporting evidence on the Chillertone website yet). This would show whether there is an observable effect on the electronic components. If there was an observable effect, it would then be worth checking whether humans could actually hear it. A second blinded listening test should be done, where players would compare treated and untreated components (without knowing which was which) and choose their favourite.
Until such evidence is produced I am skeptical about their claims. Undoubtebly people will install these cryo-treated pickups and claim they sound great, but that does not prove the effectiveness of the freezing procedure. People who buy this stuff already believe that it is going to work and their ears will tend to confirm their preconceptions.