What are these blue edges, when importing OBJ's?

I imported two different models in OBJ format, one I downloaded from some site that was originally made in Max and another one (on the photo) I made with Sketchup, both had these lines on some of their edges, what are those and how do I get them to be black, like the rest? I am not experienced with exporting and importing models that much, so maybe there’s an option I clicked, I don’t know…

Blue edges normally signify an edge which has been marked as “sharp” (in edit mode, ctrl+E, "Make Sharp / Clear Sharp). It affects the smooth shading.

Yes either marked as sharp, as said, but could be also a seem… depends on how the import-file alters some colours in the view-port.