All protrusions (air conditioners, vents, ect.) on the roof should be checked and if not working, replaced. All fasteners should be checked. Stripped fasteners or badly rusted fasteners should be replaced with the next largest size or a lap screws. All seams that have a gap more than 1/8″ wide should be secured with lap screws. All rusty areas should be treated with RRC 600 (Rust Remover & Conditioner). A garden sprayer works very well for application. RRC is clear and biodegradable. All roofs should be power washed. Water is fine in most cases. A detergent should be used if roof is greasy or oily.