What is the ruling on selling statues and crosses, and what is the ruling on selling items that aid in polytheism?

Al-Bukhari, in his Sahih, dedicated a chapter to the demolition of images, based on the hadith of Aisha (may Allah be pleased with her) that the Prophet (peace be upon him) "would not leave anything in his house with crosses on it without demolishing it." The symbol of every false deity must be demolished, and it is not permissible to possess it, let alone sell it. The sale of a cross is not valid Islamically, nor is hiring someone to make it, due to the prohibition of selling forbidden things. It is not permissible to sell wood to someone known to be making it into a cross, and if a man aids in disobedience to Allah, he is sinful. The cross is not permissible to be made for wages or otherwise, just as idols are not permissible to be sold or made.