Quiz Riddle

[path-8]

What gets whiter as it gets dirtier? many thanks for any help

[shooty]

blackboard ?

[MASS1961]

Chalkboard

[Mojo-Jo-Jo]

A snowball fight?

[bibblebub]

a blackboard is one answer

[factor-fiction]

A chalk board?

[path-8]

thanks for all the help

[Psybbo]

whitewash?

[Jansy]

How about a blackboard rubber/eraser?