One of the strangest categories of coin reuse/misuse is coins mounted on or inside other coins. One possible reason for these strange items could be that they were made by apprentices learning the jewellery trade.
This three coin brooch comprises a silver threepenny coin inside a bronze halfpenny coin inside a bronze penny coin. The halfpenny coin is gilded. A possible 'Trench Art' piece given the dates of the coins.
A brooch with a six pence coin set into a gilded half penny coin. It might be understandable if the King's head, surrounded by his titles, faced outwards, but it forms the pin side of the brooch.
This brooch has a similar concept to the one above but the smaller coin, a six pence, is raised above the larger coin, a half crown, to form a stud. If it was a cloak fastner, with the head of King George V, facing outwards, it would make sense. But the brooch pin is placed over the King's head instead.
The next brooch is similar to the previous one, except that the smaller coin is sunk into the larger one, not mounted above it.
A third brooch of the same pattern. Clearly the reason for arranging the coins in this way was well understood at the time.