I have considered. Are you familiar with anyone who does this? Any recommendations on how to get started?
Print flyers advertising your service. Put them on car windshields in neighborhoods and supermarkets. Go door to door. Make sales. Make appointments. Rent a pressure washer. Do the service. Break even or make a few bucks. Get referrals. Do again this time you'll make a little more because you'll have more clients to use the rented equipment on. Repeat business. More referral. Buy some of your own equipment instead of renting. Build a website. SEO. Adwords. Facebook Ads. More business. More referrals. Hire staff. Expand.