You just dip the toothbrush into hot water mixed with soap and scrub. Use this sink!
How can you do that?
No you can't! You can only use a toothbrush for your teeth. That's why it's called TOOTHbrush!
Yes you can! Don't be oblivious.
Have fun with your dirty watch!
No you cannot. I'm leaving! This is so stupid.
Functional Fixedness is the inability to see a new use for an object. In my comic strip, there is a married couple fighting over something dumb. Typical. The husband tells his wife she can use a toothbrush to clean her dirty watch. However, she refuses to believe him because she thinks a toothbrush can only be used to clean teeth. She cannot see another use for this object. Therefore, she cannot solve her issue of her dirty watch.