Why it is advice that we should not clean the gold from gold Smith?

gold smith uses Chemical named as aqua Regia (mixture of hcl and nitric acid)to clean gold.This acid can dissolve gold in it and the quantity of gold decreases,that is why we should not clean our gold from gold Smith.hope the answer will help you.the left over gold in chemical is separated by goldsmith and he sells this gold(actually,which is our) at high prices to us only.