India, Feb. 20 -- Brain teasers include various types of puzzles, from maths-related questions to logical reasoning riddles. Many such brain teasers keep people intrigued and busy. And if you also happen to love solving such questions, we have one for you. Are you up for this challenge?

This brain teaser was shared on an Instagram page called SIT. The puzzle reads, "I am white when I am dirty, and black when I am clean. What am I?" (Also Read: Brain Teaser: Can you correct this equation by moving two matchsticks?)

This post was shared on February 19. Since being posted, it has garnered close to 1,000 likes and numerous comments. Many people flocked to the comments section and shared their answers. Several said, 'blackboard' is the solut...