I just saw this in my news feed. I know we've been getting a lot of Moscow Mule Cups and Mugs in sub boxes, but make sure you check it before you use it. The interior needs to be stainless steel or some other non-copper non-reactive surface and food safe material. This advisory is specifically out of Iowa, but it applies the FDA guidelines.
"The Iowa advisory says the state has adopted the US Food and Drug Administration's model Food Code, "which prohibits copper from coming into direct contact with foods that have a pH below 6.0." That includes liquids like fruit juice, vinegar, wine and Moscow Mule cocktails.
The Alcoholic Beverages Division reminds businesses they cannot serve Moscow Mules in mugs with a copper interior."https://www.cnet.com/uk/news/moscow-mule-mugs-copper-health-advisory/
Ask me for my swap profile.