1988 30' Weekender and have some stains on upper sides of vee berth. This caused by the forward quarter gunwales or stanchions leaking leaving a huge stain. I'm not sure what the material is and doesn't seem too damaged to the touch just the stain. Have removed the upper trim which showed a damp area and is going to be my winter project and am wondering what product to use to refinish the sides. Would appreciate any suggestions.