I am trying to fix old B&W photos, and have limited knowledge of gimp, please help Answered

The clone stamp tool is your friend. Click it, click on your canvas while holding [Ctrl] to set your cloning point, and paint over the blemish with minimum fuss and bother.

another tip is to experiment with the levels controls. they will help immensely when working with BW pics.

What more precisely are you trying to do? "Fix" is a bit vague L