u/Electrical_Life_2538

Throughout this home, there are water stains. Around 12 windows total. Home was built in early 2000s, and struggles with moisture buildup in the winter from humidity. The windows crank out, so the rot is on the jamb, sill and the window frame. Appears to have veneer (2nd pic from outside looking in) on the jambs and jamb extension. Would this qualify for stain removal chemicals or would it need a full sanding and re-stain? Delicate sanding+staining the veneer is what a contractor recommends.