Is it permissible to sell discarded wine bottles found in the street to a factory that recycles them into household utensils, knowing that they might also be sold to wine producers for refilling?

If the seller of bottles knows or predominantly believes that the buyer will fill them with wine, then it is not permissible for him to sell them to him. However, if he does not know or predominantly believe, but rather merely assumes, then selling them is makruh (disliked/reprehensible). The makruh falls under the category of shubuhat (doubtful matters), which are acts that attract both doing and refraining. Avoiding a large number of makruh acts leads to avoiding the forbidden (haram).