Line on playback of vhs c tapes

when I play back vhs c tapes I get lines through picture. Too many lines to bother watching. when in fast forward play most lines go away.I would like to have these put on vhs or dvd but not unless they could be cleaned up. Videos of my son as baby so they are important. They have been kept clean dry ,and warm. Any ideas as where to take them or what I might do? Thank you in advance.