I got a nib file and I hate it. If i get a big run sometimes i will cut alot of it off with a razor blade. And then sand with 600 on a stiff block and then 1000 1500 2000 then some stuff that is like 5000 it is called bufflex and it lets you know what the panel is going to look like before you buff it. I have also wiped off really big runs or mistakes with reducer and then repaint.