I've looked it up in one of my dictionaries and one of the defenitions of the noun "eyewash" is liquor. Did you ever use it for booze or hear someone use it that way?
No. Forget it.
Eyewash can colloquially mean nonsense in addition to its literal meaning.
Rover
I've never heard it used to mean either one, though I know "hogwash" as nonsense.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.