Removing leaven is a physical symbol of the spiritual process of removing sin. Yeast, like sin, multiplies rapidly and spreads like a contagion. Here are some points to consider:
Purge out malice and wickedness (1 Corinthians 5:7-8 1 Corinthians 5:7-8  Purge out therefore the old leaven, that you may be a new lump, as you are unleavened. For even Christ our passover is sacrificed for us:
 Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.
American King James Version×). These are general terms for evil, the opposite of God's will. "This is leaven that sours the mind to a great degree," wrote Matthew Henry in his commentary on these verses.
Watch out for the leaven of hypocrisy (Luke 12:1 Luke 12:1In the mean time, when there were gathered together an innumerable multitude of people, so that they stepped one on another, he began to say to his disciples first of all, Beware you of the leaven of the Pharisees, which is hypocrisy.
American King James Version×). Some crumbs are well hidden from others (and even from ourselves), but to God there is nothing "hidden that will not be known" (Luke 12:2 Luke 12:2For there is nothing covered, that shall not be revealed; neither hid, that shall not be known.
American King James Version×). David asked God to "cleanse me from secret faults" (Psalms 19:12 Psalms 19:12Who can understand his errors? cleanse you me from secret faults.
American King James Version×).
Paul warned of the attitudes that would be widespread in the last days (2 Timothy 3:1-5 2 Timothy 3:1-5  This know also, that in the last days perilous times shall come.
 For men shall be lovers of their own selves, covetous, boasters, proud, blasphemers, disobedient to parents, unthankful, unholy,
 Without natural affection, truce breakers, false accusers, incontinent, fierce, despisers of those that are good,
 Traitors, heady, high minded, lovers of pleasures more than lovers of God;
 Having a form of godliness, but denying the power thereof: from such turn away.
American King James Version×). Are any "crumbs" of self-love, pride, unthankfulness, etc., lurking in our "home"? Galatians 5:19-21 Galatians 5:19-21  Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness,  Idolatry, witchcraft, hatred, variance, jealousies, wrath, strife, seditions, heresies,  Contentions, murders, drunkenness, revelings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God.
American King James Version×also lists the works of the flesh, the attitudes and actions we too easily become infected with.
Replace these things with the spiritual unleavened bread of sincerity and truth (1 Corinthians 5:8 1 Corinthians 5:8Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.
American King James Version×). Galatians 5:22-23 Galatians 5:22-23  But the fruit of the Spirit is love, joy, peace, long-suffering, gentleness, goodness, faith,  Meekness, temperance: against such there is no law.
American King James Version×lists the fruit of the Spirit.