Is money earned from working in another country unlawful if one traveled to that country with money believed to be partly of suspicious origin or unlawful?

Unlawful money is tied to the conscience of its possessor, not to the physical currency itself. Therefore, a similar amount must be returned to its owner if known; otherwise, it should be given as charity to the poor. Whatever a person earns from a permissible occupation thereafter is lawful and has no connection to the previously acquired unlawful money. The fact that it reached the country through an illicit means does not render his lawful earnings unlawful.