YOU SAID:

The custom was to place a coin in a dead mouth

INTO JAPANESE

硬貨を死んだ口に入れるのが習慣だった

BACK INTO ENGLISH

It was customary to put a coin in the dead mouth

INTO JAPANESE

死んだ口にコインを入れるのが通例だった

BACK INTO ENGLISH

It was customary to put a coin in the dead mouth