Open the back of the old CRT television and carefully clean the dust and dirt away from the high-voltage components, usually located on the right side of the chassis looking at the back of the TV. The CRT holds a high-voltage charge where a big red or black wire connects to the glass tube so be careful. The area around the red wire rubber cup can be cleaned using a spray bottle of window cleaner, but again be careful not to get shocked... 25,000 to 30,000 volts can be present on the CRT