I traded a REO and ERA to someone who is very unhappy with it. He says there is a coffee flavor stuck in it that he can't get out. Both of them were cleaned in boiling water prior to shipping and vodka run through the tubing and bottle but there's a coffee vape flavor stuck in it. He's not sure if it's stuck in the ERA or the REO, but I don't want him stuck with a mod an atty that have an off putting flavor. Suggestions on how to get that out?