I put wd 40 on my disk brakes and it's not has good when i got it brand new help!

How do i get the WD 40 off? :( i'm not tech savy about bikes and i i thought it's good to put wd 40 on your breaks so that it doesn't rust but i realized i messed up and you're not suppose to put wd 40 on your disk breaks :( is there anyway to fix this? I do have a year warranty on it. Do you...