Thank you for pointing that out, as it happens to be that you failed to use an idiom. You comment is more of a forced proverb that sounded like you were talking about people than objects with the use of 'doesn't cry'. It's easy to confuse sometimes.
I quite like idioms! They're fun to play around with.
using soap water is the last stage before polishing a crystal is complete. There are four stages of polishing beforehand that use increasingly fine grit tumbling medium.
My proverb does also apply to people.
If someone is put to good use they are less likely to be depressed and cry about it. If someone feels useless then there will be many tears.