Shaykh Waheed Baali says:
If you are certain that really are jinn in the house and that it is
not a trick then the way to expel them is as follows:
- You should go taking two people with you to the house and say:
"I urge you by the covenant that Sulaymaan
took from you to leave our
house. I urge you by Allaah 
to leave and not harm anyone."
You should repeat this for three days.
- If you notice anything in the house after that, then you should bring water
in a vessel, bring your mouth close to it and say the Du'aa which
Al-Muhaaribi wrote to Abu'l-Nadr, which is quoted above. After saying this
Duaa, sprinkle that water in every corner of the house, and put
some in every spot, then they will depart, by Allaah's leave.
- Continue to recite the Qur'aan in the house especially
Soorah Al-Baqarah and offer Nafil prayers and pray
Qiyaam at night in the house.
- Purify the house of everything that involves disobedience towards
Allaah . [1]
[1] Waqaayat Al-Insaan
Taken from, The Jinn and Human Sickness -
Remedies in the Light of the Qur'aan and Sunnah
by Dr. Abu'l-Mundhir Khaleel ibn Ibraaheem Ameen
Foreword by Waheed ibn 'Abbus Salaam Baali
Translated by Nasiruddin Al-Khattab
Edited by Dr. Abdul Ahad (Alig.)