Due to popular demand, CTBusters has finally substituted the copper/zinc pennies with pure copper discs. Now you can scrub those contacts clean without messing up those poorly copper-plated pennies that we used for years. CTBusters absorbs the extra expense, so, no increase in price, just quality.
For too many years we resisted doing this. The new pennies from the bank have suffered in quality quite a bit. They come though with radial scratches that used to make a coin more valuable, not anymore. People like to get the contacts real clean but here's a tip: It's not that necessary because copper is naturally anti-bacterial. Hospitals now use copper in the patient's bed's handrails to prevent the transfer of germs. Our new all-copper contacts do the same thing.