Is it permissible to work for a company whose earnings are unlawful if my work is lawful and my salary is lawful?

If the company's funds are acquired through unlawful means, then working for it is impermissible. However, if the funds are mixed, it is permissible to engage in the lawful aspects of the work, provided that one does not directly perform or assist in unlawful activities. It is obligatory to seek out pure earnings and avoid unlawful and doubtful matters.