Dan,
I'm sure that works on sails,
but, the late Randy Urinak,-Houston,Galveston, would rave about that stuff to return the bright finish to fiberglass hulls!! Same stuff?
Oxalic acid will bleach the hulls and give you a "white" finish, but it will not give you a "bright" finish. It actually makes it easier for the hulls to discolor again. It does a great job removing stains but you must wax the hulls immediatly after using it.
