Wipe dirt and dust from the plastic window with a damp rag.
Pour 1/8 of a cup of mineral spirits onto a clean rag. Wipe the mineral spirits over the tree sap on the plastic window. Allow the mineral spirits 30 minutes to soften the tree sap.
Wipe the softened tree sap from the plastic window with a damp rag.
Mix 1 tsp. of mild dish soap with warm water in a bucket. Wash the mineral spirits from the window with the soapy mixture and a sponge.
Rinse the window with cool, clean water and dry with a lint-free towel.
Nail Polish Remover
Moisten a cotton ball with nail polish remover. Wipe the cotton ball over the tree sap. Use several cotton balls saturated with the nail polish remover, depending on the amount of tree sap on the plastic window. Allow the nail polish remover to remain on the tree sap for 20 minutes.
Wipe the dissolved tree sap from the plastic window with a damp cloth.
Pour white vinegar in a spray bottle and spray the plastic window. Wipe the window clean with a damp rag, and dry with a lint-free cloth.