i need help with oil pastels

[assassinsilence]

for an art class, i made a movie poster for dark knight. but when i used color pastels, i thought to lay a peach skin color as a base color and to trace in the wrinkles in black. then i went over it with white and it looks dirty as hell.

how do i clean that up? it looks all sloppy

[Meloncov]

You could scrape off some or all of the pastels with a knife.

[assassinsilence]

i tried that and it kinda works, when im done ill post the pic up