How to get rust off ice skate blades?

I have Riedell 133 ice skates. I just got them a few weeks ago, But there is already rust, and scuffs on them. I know how to get the scuffs out, But not the rust? Does anyone know how to get the rust out. I just got them sharpened when i got them (BTW how often do you need to get them sharpened?). So if anyone knows please answer :)