delete curves outside a perimeter

Hi guys,

I have this set of curves (img02)

I've splitted them with shatter, using the perimeter of that square.

What i'm trying to do now is to delete the curves outside the box (img01). The problem is that the tree that shatter gives to me is a bit messy and it's difficult to find a pattern for culling items.

I would like any suggestion to do that. Maybe my workflow isn't correct and shatter is not the right component