Is it permissible to engage in trade with non-Muslims, even if they are of good character? Is it permissible to do so with non-practicing Muslims? Is it permissible to sell something of high value to non-Muslims? Is it obligatory to give charity to purify such funds, especially if their source is unknown?

A Muslim's partnership with a non-Muslim in trade is permissible, though disliked. The Maliki and Hanbali schools stipulated that the non-believer should not unilaterally manage the affairs.

It is disliked to partner with a Magian, an idolater, or anyone who worships other than Allah, even if the Muslim is the one who manages the affairs.

The Prophet, peace and blessings be upon him, forbade partnership with a Jew or a Christian, unless the buying and selling were managed by the Muslim.

Selling an item of high value to a non-Muslim is not forbidden by Sharia (definition), and charity is not obligatory merely due to not knowing the sources of their wealth.