I'm considering how to proceed with /lexicon (which I think of as my present Great Work, though it's a subpart of the lifebox; I contemplate a reorganization of the whole thing, to facilitate access to the complexities I've collected in the last 12 months. The lexgather page is a prime candidate for reform.
Reading through them today, I chanced upon Victor Mair on The conceptual origins of "brainwashing" (6xii25) and Mark Liberman on "Maplewashing" (13xii25) and started to assemble an expository page for *-washing, a verbal noun easily traceable to Matthew 23.27, where Jesus likens the Scribes and Pharisees to 'whited sepulchres' (which look nice on the outside but hide the corruption within), a metaphor for hypocrisy/profound insincerity. And in Heart of DarknessJoseph Conrad described Brussels as a "city of whited sepulchres" that lived upon the horrors of Belgian Congo genocide. There's an unescapable parallel to Tom Sawyer's whitewashing of Aunt Polly's fence, too.
Quite a few marvelous resources to explore *-washing as a metaphorical suffix:
google AI overviewsuffix -wash wiktionary
A Way With Words on 'whited sepulchre'
pinkwashing Wikipedia
washing: Prefix, Suffix and Derived words niftywords.com
List of words that end with WASHING thewordfinder.com