If you have asphalt roof shingles, used vegetable oil can help bring them back to life. You will need a lot of oil — around 1 gallon for every 250 square feet of roofing. First, heat the used oil, let it cool, and strain it before staining. You can apply an even coat to the shingles using a paintbrush, spray, or roller to moisturize the material and extend its life. Ensure your roof is clean and dry, all holes are sealed, and broken shingles are replaced before applying the oil. A weekend with no forecasted rain is the best time to revamp your roof.

Source: housedigest.com