We find that the rate of track etching of heavy-ion tracks in Lexan polycarbonate is greatly increased when the track-containing plastics are stored in a container in which a spark-discharge is occurring. We describe a series of simple experiments, using a Tesla coil as the spark source, that have led us to the view that the effect is caused by the interaction of excited gas species with the stored tracks. It does not appear to be caused either by a direct electrical effect of the discharge or by light given off by the spark. This new effect can potentially be used as a method to both sensitize and stabilize plastics containing charged particle tracks.