At a talk I gave a week or so ago, I mentioned Vino Sano Grape Bricks. That led some in the audience to follow the thread, and I’ve turned up a few more fun photos on this subject.
For those who don’t know, a grape brick is a dehydrated block of grape juice and pulp that was sold–quite legally–during Prohibition for people to make their own wine at home. Instructions couldn’t tell you how to make wine–that would be illegal–so they told you how NOT to make wine. Don’t add sugar and yeast and don’t let it sit in a warm place for 21 days or it might ferment! There were other brands too, but Vino Sano was the leader.
Here are a few other interesting illustrations I found. A want ad for salesmen to sell the product. This also revealed the price of a grape brick ($1.25), something I hadn’t known. 
And here’s another advertisement:
Mary Miley's Roaring Twenties 
The Vino Sano Grape Brick, thought to be one of the last few in existence, has been put on display by the Ontario Museum of History & Art, and dates to around 1930