When weeding a garden, by turning over the soil to cover the weeds, the soil may look very clear or free from weeds for some time. You may think that you have gotten rid of all the weeds, but in due course of time, those seeds that are under the soil will gradually grow again. However, a fried or burned seed cannot fructify. Thus, the seeds of sinful desires within the heart can be burned up in the fire of Krishna consciousness. A person who has adopted unalloyed devotional service to Krishna can uproot the weeds of sinful actions with no possibility that they will revive.
LFD Vol 3,Uprooting Sinful Activities, Pg 203, 2nd last paragraph onwards"