The rusted, padlocked suitcase sat alongside a porcelain coffee service set, decorative enamel-finished eggs and a vintage gas-powered model of the 1965 Chaparral II race car prototype.
Auctioneers got the suitcase open just before the sale on Saturday and found three blocks of military-grade C-4 plastic explosive, two tubes of a similar plastic explosive, a blasting cap and some dynamite.
Workers quickly called 911. The Conway Fire Department's bomb squad put the aging explosives inside a special container and drove them out to an isolated spot to destroy them, district chief Jon McMahon told the Log Cabin Democrat newspaper.
The auction went on as planned.
Faulkner County sheriff's office Maj. Andy Shock said the explosives had deteriorated over time and likely were at least 15 years old. Shock said that age put the C-4 at the outer limits of its shelf life, meaning the explosives were unstable and even more dangerous.
The items at the estate sale belonged to a U.S. Navy veteran who recently died, Shock said. Deputies continued to investigate the incident, but charges weren't likely as the presumed owner of the explosives is dead, he said.
But just in case there was any doubt, Faulkner County Sheriff Karl Byrd made sure to stress that owning dynamite or plastic explosives without permission is "definitely illegal."