All you need to do is to put the object in your hands and imagine a bright shining light shimmering from both of your palms.
Next you need to direct the energy by your thoughts and words. You do this by saying a certain chant like:
Cleanse, Cleanse, Cleanse... etc
You dont need to see it or even feel it all you need to know that the energy is their and that you are projecting it with your intentions.
Do this until you feel you need to stop and it is cleansed. YOu can even say a little prayer over it asking a spirit or even a deity to bless it