The answer to 'how to clean flashing repair' is to first inspect the flashing for any damage or corrosion. Clean the flashing by scrubbing it with a stiff-bristle brush and a mild detergent solution. Rinse the flashing thoroughly with clean water to remove all soap residue. Once dry, you can apply a thin coat of roof sealant or flashing cement to any cracks or gaps to seal them. This will help prevent future leaks.
It's important to clean flashing regularly, typically once a year, to maintain the integrity of your roof. If you notice significant damage or corrosion, it's best to call a professional roofer to assess the situation and make any necessary repairs.