169. Items Designated for Idolatry
Avodas Kochavim 9:6
If an item is designated for use in the service of an idol in a particular location, that kind of item may never be sold in that place to the worshippers of that idol. Things that are not so designated may be sold to them without asking how they will be used. However, if an idolator mentions that he is purchasing the item to be used in idolatry, one may not sell it to him unless he does something that disqualifies it for that purpose. One could sell him an animal that is missing a limb since it can no longer be offered as a sacrifice to the idol.
Avodas Kochavim 9:7
One may sell things that are designated for use in idolatry if they are mixed with things that are not used for that purpose. For example, one may sell pure frankincense together with black frankincense without asking for what they will be used. We do not have to be concerned that the buyer will sort out the pure frankincense and use it for idolatry. The same is true in similar cases.