Must break body before immerse in Mikveh:
The body of a Jew is similar to an earthenware vessel, having been created from the earth. Now, only metal and the like can become purified through immersion in a Mikveh, in contrast to earthenware. Earthenware must be broken to be purified. The body of a Jew has the same status; in order to purify the body, it does not suffice to immerse it in a Mikveh alone, but rather one must preface this with a broken heart, and bitterness over one’s lowly spiritual state. One needs to then make a firm resolution to leave his evil ways and accept the Yoke of Heaven. Only when the body is immersed with this spiritual preparation can the waters of the Mikveh purify it.
 Keser Shem Tov 2