In Jewish thought the removal of leaven has been extended metaphorically to refer not only to the annual extraction of bread and yeast from our homes but also to our repeated efforts to seek out and remove what corrupts us and makes us less than whom we wish to be.
For example, Rashi (the 11th century French sage) spoke of "the evil inclination, which causes ferment in our hearts" (Commentary on the Babylonian Talmud, Berachot 17a). The metaphor of ferment is an intriguing one. Dough rises because bubbles of carbon dioxide inflate it as microbes in the yeast break down sugars in the flour. By analogy, motives like pride and one-upmanship break down our resolve to do good and inflate our ego.
May this Passover be an opportunity to seek out, and overcome, the leaven in our hearts.