To keep algae growth from your bird bath drop some copper pennies in. I have what I would call a normal size bird bath & I use 7 pennies. The reason for the pennies being is that before that year, the pennies contained copper, a natural algicide.
Spiral Earring Hoops with Coin Pearls, Interchangeable dangle earrings in Silver, Gold, or Rose Gold
The Mysterious Worldwide UFO Coins The century French copper coin“Is it supposed to be a UFO of some sort, or a symbolic representation of the Biblical Ezekiel’s wheel? Dating back to this mysterious coin appears to be another example of the first