Wooden Garden Benches OK How Do You Get Sap (from A Knott In A Garden Bench) Off A Tee Shirt?

OK how do you get sap (from a knott in a garden bench) off a tee shirt? - wooden garden benches

My wife is a discoloration on the shirt a bleeding Knott from a wooden bench in the garden and can not be removed tissue of any proposal to remove the stain