To do a silent barter, one group of traders would go to a certain place, leaving whatever they are offering to trade. The other group of traders would then decide if they would like to accept the goods (usually salt or gold) that were left. If the goods met with approval, the second group would then take the goods, leave their own goods in return, and leave because the person accepted the offer. This system of trading was used mostly in ancient Ghana. The popular things they sold were gold and salt. Another system was face-to-face trading using hand signals.