As long as you can access them safely, it’s fairly easy to clean soffits and fascias. Using a sponge and warm water to scrub them is a good way to get off most types of dirt. You might want to add detergent or bleach to the water to make it more effective. Once you’ve scrubbed your soffits and fascias, rinse them with clean water to make sure you’ve got all of the dirt and detergent off.