Is it permissible to accept a job as an electrical engineer in a factory that produces plastic bottle caps if one of its products—whether inside or outside Egypt—is caps for beer bottles?

It is not permissible to work in a factory that produces bottle caps for beer, because it constitutes cooperation in sin. The Prophet, peace and blessings be upon him, cursed ten people regarding alcoholic beverages. However, if the caps are manufactured outside of Egypt, it is permissible to work in the factory inside Egypt, because the ruling regarding the owning entity of the factory is akin to the ruling concerning a person whose wealth is mixed (with unlawful elements), and dealing with him is considered disliked (makrooh) but not forbidden (haram).