Letter sent by PostMuse (the USA). It is an envelope made out of an old calendar. The beer is beautifully painted on. It seems a real one! I am just happy that this arrived before Ramadan starts... (Probably the post office workers are neither eating nor drinking during the daytime in Ramadan. So I would not want to disturb their fasting with beers).
Among other nice stamps, she included this one, issued on 1971 and wrote it is one of her least favourites. However, I like it. Not just the fact of receiving old stamps, which is great. But I also love the vintage design and the colour.
Besides this, it matches perfectly with the beer-themed envelope, does not it? Remember that you must consume beer envelopes (mail art in general) in moderation.