Hair Quandry!??...

[x-Dahlia-x]

Everytime I straighten my hair recently it foes really greasy, especially at the back. My hair was completely clean before as well because I'd washed it that same day! I never noticed them doing this when I first got the straighteners and they're not some cheap rubbish ones  with ceramic coated plates, it's pure ceramic. Also my sister has the same straighteners and it doesn't do it to her hair although she has naturally wavy hair and mine is dead straight but with kinks at the end...hmmm! Can anyone shed any light? I'd be v. grateful as I want to straighten it because I'm going out at the weekend! Thanks.