thanks guys

sweet! here the result

NOTE: I downloaded Sketchup today, and i haven't read any basics tutorial.

Im making a concept sunglasses casing for my school project.
and I want a 3d model for my case (to put it to my folio), So i downloaded sketchup and start to make a model of it.

I have done 3D model casing but this lines really annoys me:

Is there a way I can remove that.

NOTE: i tried erasing it but this happens: