Previously trimmed Quicktime videos

Hi, this is connected to a closed discussion: Remove previously trimmed clips from a Quicktime File I have many files that used to play fine on my iPhone and Mac, but not on PCs. The discussion pretty much says you have to permanently delete the trimmings while you are editing them. Is there a way to do this after the fact (IE the file has been "saved as" but still plays longer on VLC etc.? the edits were done in the middle of the clips as well as beginning and end.