Rub oily spills with plain white chalk to pull the oil right up and out, as we’ve told you before. After you rub it, leave it alone for about 10 minutes to let the chalk residue do its job, then ...

Since then, Positive Chalk has participated in more than 100 events. And Chelsea Ritter-Soronen, owner of Chalk Riot, a women-led street art crew, said Chalk Walk was her dream collaboration.