'Fit' Vegetable wash - MSDS - lists ingredients as:
Water
Citric Acid
Ethanol
Grapefruit oil terpenes
Sodium Lauryl sulfate
I suppose you could replicate that with a sink full of water, dash of lemon juice, dash of vodka, and a drop of dishwashing liquid...
sorry, I don't know how you source the grapefruit oil terpenes, maybe a bit of pureed grapefruit skin ?
I always wash my fruit and veg in water...I quite like the 'chemical' properties of ordinary H2O with a dash of additives...