The house that I have was builted in 1978. The shower heads has not been cleaned, there are disposits on them. I am trying to replace one of the shower heads, for many reasons, however, I am running into difficulty. Because of the disposit it is really hard to remove the head. So, I will tell you what I have done so far, and any help that you can offer will be greatly appreciated. I have tried to remove the shower by the arm, but the arm is tight just like the head. I have used WD-40 to try and lubricate the fixture. I have also tried using a Vista grip wrench with no luck. So, once again any advice or suggestions that you can give will be appreciated.