What movie black and white about a man who puts money under his floor boards squirrel drops it into the house below in uses to help people becomes rich?

You're likely thinking of the 1947 film "The Bishop's Wife" starring Cary Grant.

Here's why:

* Black and White: The film is indeed in black and white.

* Man Hiding Money: Cary Grant's character, Dudley, hides money under the floorboards of his home.

* Squirrel: A mischievous squirrel steals the money and drops it into the house below, which is occupied by a struggling family.

* Helping People: The family uses the money to overcome their hardships.

* Becoming Rich: While Dudley doesn't become rich from this, the movie emphasizes the importance of helping others and the unexpected ways in which good deeds can bring happiness.

Let me know if this is the film you were thinking of!