My periodic table poster is now available! Spark plug. These spark plugs, now discontinued, were made with a gold-palladium alloy center electrode. Some people swear by them, other people swear at them. In any case, the company (Champion) replaced them with a platinum version. Here's an interesting article about different elements in spark plugs. Source: eBay seller drsusphd Contributor: Theodore Gray Acquired: 10 January, 2003 Text Updated: 11 August, 2007 Price: $8/4 Size: 3" Purity: <50% Sample Group: Spark Plugs