Hey All,
I was selling stuff on eBay and one item went for a real low price, so low that I ‘took a bath’ on that auction. I broke even on another auction, ‘it was a wash.’ And on another auction I made a big profit, ‘I really cleaned up.’
And then I was wondering why…
Take a bath = losing money
it’s a wash = breaking even
cleaning up = making money
Cause if you are really taking a bath, aren’t you also cleaning up by washing yourself?
What’s the straight dope?
-Sandwriter, Watertown Mass.
These are merely slang expressions and are not to be taken literally. 
Although your particular idioms are not listed here, this interesting website is dedicated to giving such meanings and origins.
The first and last expressions are mirror images of each other. To “take a bath” is old gambling slang for “to get cleaned out,” or to have someone “clean up on” you.
I’m not familiar with this meaning of “it’s a wash.” To me, it’s short for “washout,” a total failure; from slang for a roadbed or railbed that’s been washed away by flooding. However, people do use it that way. It appears to refer to the act of “washing” away a debt.
The term for “coming out even” that I use is “it’s a push,” referring to a gambling result that returns the stake but no winnings.
It’s too hot to delve into this more than superficially.
Wash was used as early in print as 1859, but it was originally a phony sale between the seller and the buyer for nefarious purposes. But that was where it came from.
To clean up was used in 1867 to mean “a great profit; a windfall.” From the gold fields of California.
To take a bath is only cited from 1937, in gambling slang as was said earlier.
So, don’t make too much of the coincidences.