the.com/whitewash
A coat of cheap paint applied to walls and reputations alike.
means To cover up wrongdoing, flaws, or dirt with a thin, deliberately flattering layer.
from From literal whitewash — a watery lime paint that brightened poor walls cheaply — coined into metaphor by the 1700s, when people noticed it hid stains as well as shabbiness.
Tom SawyerConned friends into painting his fence.
Lime-basedReal whitewash kills mold and germs.
Casting useNow also means erasing characters' ethnicity.