Removing line bits after using image trace and path finder

I'm creating a simplified butterfly wing for a project I'm working on.
I've imported a jpg then used image trace to make a vector with 10 colours.
I now want to create a black line around the outside of the wing.
I've made a copy, filled it with white, added a black stoke then used pathfinder to create the outline. Unfortunately, the result is filled with these speck and short lines. Is there an easy way to remove these
and make a clean outline stoke? Thanks!
R.
(can't work out how to add a .ai file)
