Reverse graffiti, also known as clean tagging, dust tagging, grime writing, green graffiti or clean advertising, is a method of creating temporary or semi permanent images on walls or other surfaces by removing dirt from a surface. It is often done by removing dirt/dust with the fingertip(s) from windows or other dirty surfaces, such as writing ‘wash me’ on a dirty vehicle. Others, such as artist Moose, use a cloth or a high power washer to remove dirt on a larger scale. - Source
Fun fact: the Polish government officially appointed a parliamentary team called “Stop the ideology of gender” which is supposed to “combat the negative influence of gender ideology on the Polish family and gender identity of man”. This means that there is an official government organisation whose goal is to make sure citizens do not cross boundaries of their gender roles which were “assigned” to them by God, and “protect” children from sex education in schools.