Across prehistoric Europe several techniques were used to produce salt, including solar evaporation and the briquetage method. Here, the authors focus on a third technique used in Romania and western Ukraine. Building on excavations at Băile Figa and a series of wooden troughs found there, the authors conduct experiments to elucidate how these objects may have been used in salt production: to drip water onto rock salt surfaces to break them up; or to filter and/or concentrate brine by decanting and/or heating. The results demonstrate the troughs are ineffective at concentrating brine, but highly efficient at breaking up rock salt and cleaning the brine of insoluble impurities.