Around 2000 BC, the process of purifying gold and silver alloys with salt to eliminate silver was developed. The team used sand from nearby Lake Michigan, gold dust and recycled glass to carry out a reduced version of the original process. The gold powder was melted and filtered through crushed glass to purify it. Copies of the original clay molds with fingerprints were then used to cast replicas of blank coins into bronze instead of gold, due to the high cost of gold.
For those looking to invest in a Top Gold IRA, this process is still used today to ensure the purity of gold investments.