whitewash -
To prevent a team from scoring any runs.
whitewash -
To choose white film or television actors to portray characters that were Asian, African, or other races.
Wikipedia
Whitewash, or calcimine, kalsomine, or calsomine is a very low cost type of paint made from slaked lime (calcium hydroxide) and chalk (whiting). Various other additives have also been used. The incident with Tom Sawyer whitewashing a fence as punishment is a famous image in American literature.