Smudging has been used for centuries as medicine and for spiritual purposes. The blue sage is also known as 'Grandmother's sage', it cleanses and heals. 
It is the most powerful herb for negative energies, as it is also used for exorcism by the Catholic Church. Sage is also used to improve health.
 
First, light the smudge stick, and when there is fire in it  blow it out, as it is only the smoke you must use. Always start by cleaning yourself first, you do this by distributing the smoke from the bottom up afterwards. After that, all premises, i.e. all door frames, and window frames and all other places where there is an entrance to the home. And then say something like:
 
'Only light, love and spirituality are welcome here'
 
and it is done in all rooms. Once you've done it the first time, it's just a matter of keeping it straight. It can be anything from once a week to once a month, depending on what you feel like.
 
If your smudge runs out, just turn it back on and continue, don't leave it on a flammable surface afterwards, use it with care and don't let children use it.