After another company sent a power washer to clean our deck, he left a terrible mess in a communal area below, which is shared by 3 local businesses. Dirt and grime was everywhere, all over the concrete floor and walls, and all over art supplies from one of the businesses.
I found Onyx 23 on Thumbtack and he came to save the day. He was on time, professional, and clearly took great pride in his work. The before/after photos show the incredible transformation. He even made sure to squeegee all of the water into the drains while ensuring the muck and debris didn't get in to clog them.
I recommend Onyx 23 highly and will save his information for any future clean-up/power washer needs. If you're reading this and need a power washer or professional cleaning, you've found your solution.