Usually,
it was Nestle's Quik here, rarely Hershey's syrup ("because that can is SO messy") and once in a while Ovaltine, which I didn't like then, but like now.
We had heard of Bosco, but for some reason, it never appeared in our kitchen.
My current obsession is the Hershey Dulce De Leche, however.
Lawrence/Maytagbear