To sprayhand sanitizer and disinfectant all over the past, so that people forget what it was really like in favor of what they read about it being like in a book.
When a white (caucasian) man has rough/aggressive sexual intercourse with a white (caucasian) woman who has been blacked, typically for revenge or self-vengeance. This may go on for about a few hours at least.
When somebody turn a dark skinned character white because they think their skin colour is bad so they change them white and think that they "fixed it".
When somebody turns a dark skinned character white because they think that their skin colour is bad so they turn them white and think that they "fixed it" or "made them better".
Whitewashing is used for harmful intentions.
Person 1: "Eeugh she looks bad, so made her better!"
Person 2: "You are whitewashing her... That's not good."