Can someone post a photo of this overspray? I guess we're talking about the lacquer coat, which is spun off as CDan mentioned. Ink absorption layers, thermal printable layers, "diamond coat", etc. are all silk-screened and UV cured. In poor quality control situations, there may be insufficient ink used on a portion of the screen resulting in a non-uniform finish, but nothing that would look like an overspray.
So, I can't personally recall ever seeing anything that would make me think "overspray" and I've handled tens of thousands of discs. Maybe a picture or two might help.
But, most importantly, how about burning some instead of tossing them? Then we'll know if they're good or not, right?