So if I buy a bunch of candybars and sell them for a profit, and someone buys some of my candybars with money he made selling cocaine, have I laundered his drug

So if I buy a bunch of candybars and sell them for a profit, and someone buys some of my candybars with money he made selling cocaine, have I laundered his drug money? He still needs to sell those candybars to get clean money. Using illicitly obtained money to buy something that can then be resold for clean money is a very common money laundering technique. But it's the person buying and reselling assets who is committing the crime, not the entity initially selling goods. Otherwise Walmart would be the biggest "money launderer" in the country.