HAve any of you ever cleaned blue stone? I have a guy I am doing paver work for that has blue stone with some oil stains from a car. I am planning on removing it with a heated pressure washer. If that doesn't work I have the option of trying an oil remover like Techniseals product. Anybody have experience with this stuff on blue stone? I don't want to discolor it if its a sensitive material. Anybody ever sealed blue stone with an invisible sealer like a siloxane? how did it work? Thanks fo rthe help!