Can those who do not rely on heter mechira (selling) for real chametz keep Cointreau over Passover? What is the origin of the alcohol in Cointreau? Does Cointreau contain grain alcohol from, e.g., wheat or barley?
This website seems to imply that Cointreau is even kosher for Passover, but I have been unable to find any corroborating source for this assertion from a certifying authority or from the Cointreau website.