[DaJudge]

Go to an auto paint supply store and purchase some prep solve. Get a cookie sheet from the wife's kitchen cabinet and lay the build sheet in it, gently pour the prep solve into the cookie sheet until the prep solve covers the build sheet. This will remove any grease and tar that has impregnated the build sheet and will not damage it. Let soak for an hour or so and the stains and dirt will lift right out without damaging the document. When remove gently lift the build sheet from one end and pour prep solve over the build sheet to rinse. Let hand dry in a safe place and it will lighten and clean it right up.

I learned this from a Ford guy when I owned my two Boss cars.

Mike