For a treasure hunt ok, but nothing more

We bought the coin for a treasure hunt (child's birthday). The coins are very thin and light, some were already black tarnished (but not too many). Our coins have not smelled unpleasant. For the price I certainly expected no miracles and for the purpose they served. On some coins, we have written the names of the guests and the birthday child. This was the conclusion to a sachet (Encaustic are by now standard on children's birthday parties ...) will be exchanged. Also were candy and "gems" in the chest.

Meanwhile, the coins are as play money in the shop in operation.