I have been reading here alot as of late.I have gained alot of info on roof cleaning.No pressure roof cleaning is the way to go.I just marvel at apply and let mother nature do the rest.I am wondering how you do the edges of tile?Wont the formula hurt the metal drip guard?Will this hurt metal ,wood fascia or all types of siding due to over spray?Would not be good to have a great looking roof but the customer notices spots on her gutters and so forth.Do you mask?I am a newbie and always want whats best for the customer.Thanks