Purgatory
 
  What is purgatory, and who goes there?  
  The Catholic doctrine on Purgatory is very short.  There is not much known about Purgatory.  It may be a place or a moment in time. What is known is that there is a final cleansing prior to entering heaven.  The bible tells us that nothing unclean can enter heaven  So purgatory is for "all who die in God's grace and friendship, but still imperfectly purified, are indeed assured of their eternal salvation, but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven"  according to the Catechism of the Catholic Church, paragraph 1030.

Many people think if we ask for forgiveness, we are ready for heaven.  However, just like when a surgeon operates and cuts out a disease there is still a scare.  Likewise when the divine surgeon. Jesus, cuts out your sins, there is still a scar.  It is that imperfection which must be purged prior to entering heaven.