My in-laws gave us a plow, it was used by her grandfather, pulled by a mule. (she has pictures somewhere). Anyway I had expressed an interest in it years ago when I saw it in their old barn, for a garden decoration. They brought it to us this weekend. The wood handles are faded and rough, the blade and metal parts are rusted. I would like to preserve the old aged look, at the same time preventing it from aging farther. It will be sitting in a flower bed in the elements, what can I spray it with that would be clear and protect it?