Magnecor wires last much longer than any other wires, and for this reason the wires will, in time, become coated (usually in patches) with assorted and unsightly waste materials that originate from roadways, oil fumes, waste coolant, road dust, mud, deteriorating engine belts and tyres (particularly on engines that are exposed, such as a drag car). Some of this material will contain carbon, and in certain circumstances become conductive. An excessive layer of carbon deposits could cause sparks to be induced into it and grounded if spark plug gaps are wide, and misfiring and other drive-ability problems could occur. This is an unusual occurrence, but it can happen on much-worked-upon engines that have been fitted with the same Magnecor wires for an extended period of time — so if you notice black deposits on your wires, you should clean them.
To clean wires; Use a mild solvent, even alcohol will work, but make sure any flammable solvent you use is completely evaporated before you crank the engine. Common solvents will not damage the silicone itself, but a solvent that is too strong may remove the printing (ink) from the cable which identifies the cable’s conductor (if you are unsure, you should experiment with a small patch first).
Do not use a water-based cleaner (unless you ensure the wires are completely dry before use) since a layer of water is also conductive. Do not use any sort of abrasive or corrosive cleaner, which could damage the both the wires and other engine parts around the wires.
If fitted correctly, and not damaged or exposed to conditions beyond ratings for the wires, Magnecor Race Wires will last indefinitely, however like any other part on your engine, they should be cared for correctly.