Cleansing is defined in Webster's Dictionary as to clean; especially : to rid of impurities by or as if by washing. Cleansing doesn't always have to involve water. It can involve fire, smoke, and fasting as well. Below find simple guidelines as to some of the different kinds of cleansing.
Baths and water are a way of cleansing. If you have had a rather tough week, perhaps a full bath soak with relaxing music and incense, is called for. It is recommended to add sea salt to the bath keeping in mind that you are letting the water wash all remnants of the dirt and negative that accumulated over the week away. This should not be a bath with soap and the regular routine that "normal" baths are. Some people ritually cleanse every full or new moon. How often is up to the individual but if you are doing alot of ritual or Majick or working in a tough job or circumstances, clean more often. Some people have also cleansed by immersing in fresh running water or at the minimum washing their feet and hands in stream water. "I am gonna wash that man right outa my hair" is a familiar showtoon song and yet when we end a bad relationship, perhaps it might be best to have a ritual cleansing to "wash that man right outta your hair". Washing away that negative energy build up from a bad relationship might be just what is called for to start anew. It is as important in cleansing as it is in ritual to keep your intent clear.
Fasting is also a way of cleansing. Many people fast when they are preparing rituals. Fasting cleanses the body of other residues that are inside not out. Other people fast just before the four main fire festivals. If your life has just gone through major change, it may be a good cleansing to fast, purifying yourself for the new life that has presented itself and thus leaving the old life behind. There is much history of fasting before Majickal works and even before rituals, in both Celtic and Native American cultures to name a few. Please consider your health if you want to fast. It is not very cleansing to be ill afterward or even in hospital.
Burning is a way of cleansing. If you have notes or writings that have recorded your pain in a relationship, Burning them ritually is a way of cleansing and starting a new period in your life as the olds pains are burned away. It may not be necessary to burn the originals but copies as they hold the intent of your working or ritual. Just a burning a copy of a picture of the two of you might make be a ritualistic way to affirm the relationship has ended and you are starting anew. It is again up to the individual doing the working.
Which ever way you choose to cleanse, keep your intent in mind. Keep your mind clear. Remember that you are leaving the old dirt behind and so step out of the bath into clean clothes, thus signifying mentally and physically that you are now clean.
As always, if you feel uncomfortable, don't do it. If adding salt to the bath, seems wrong, work with the water and yourself until it feels "right". A certain kind of incense or smudge may be right for one person and not another. There is no right or wrong way in cleansing. The main point is to clean away those spirtual and emotional things that may be clinging to you, like dirt. In certain tribes and groups, cleansing can be it's own ritual. And that is fine too.