It's not the voltage that kills, it's the amperage. 110V will kill at very small amperage. The only way you could be slightly safe is to put them on a GFCI... ground fault circuit interruptor... you may have one in the washroom or outside.... but ask someone who knows what it is and can check to make sure it's working properly.

BTW, don't use glass ornaments. After they break them, they may eat them, let alone walk on them.