How do I clean the record heads on my video recorder?

Tommy quickly replaces the burnt out vacuum tube on the device and plugs it in. The tendrils of energy are drawn back into the tower, releasing her intended victims and restoring her previous ones. The Wire screams, and the portable set goes dead. The Doctor returns to the control room, and smugly tells Tommy that he turned the transmitter back into a receiver and trapped the Wire in a makeshift video cassette recorder. "She" is now trapped on a Betamax cassette.