What's the best way to get rid of scale

[SlipperGirl]

So a girl that I know was getting rid of here orchids and offered them to me, so logically I said ya I want the orchids! Anyway so I picked them up today and found out that they were sitting in water so the roots look horrible, they all need to be repotted, only two have name tags on them, and they have a really bad infestation of what I think is scale.

So my question is what's the best way to get rid of the scale? I have read of a couple of different ways but was hoping that someone that has had scale could tell me if one way is better then the other.

Here are some pictures of the orchid that has it the worst of any of them. Thanks for any help.