Selling haraam and doubtful things

It is not permissible to sell them because when Allaah
forbids a thing He also forbids its price. Ibn ‘Abbaas (may Allaah be pleased with
them both) said: “The Messenger of Allaah
(peace and blessings of Allaah be upon
him) said: ‘Allaah has cursed the Jews because fat was forbidden to them, but they
sold it and took its price. When Allaah forbids something he also forbids its
price.’”

(Reported by Imaam Ahmad, 2546).

With regard to doubtful things, it is better not to sell
them, so as to be free of any blame, as the Prophet
(peace and blessings of Allaah be
upon him) said. Al-Nu’maan ibn Basheer said: “I heard him saying, ‘I heard
the Messenger of Allaah
(peace and blessings of Allaah be upon him) say: “What is
permitted is clear and what is prohibited is clear, and between them are doubtful things
which many people do not know about. Whoever avoids doubtful things will be on the safe
side with regard to his religion and his honour, but whoever falls into doubtful things
will fall into haraam things.”’”

(Reported by Muslim, 2996). And Allaah is the Source of Strength