A customer asked me if I would be able to power wash, add polymeric sand, and seal his paver driveway. Never did this before, but I have done a lot of research and I am ready to give it a try, but I have a few questions. 1. When power washing, what chemicals, if any, do you guys recommend to clean up the pavers? (It's a driveway, so there are many oil and tire stains.) 2. The customer said the price was a lot higher than he thought it would be. He wanted to cut out the sealant part of the job to reduce the cost. Is it okay to add the polymeric sand without using a sealant afterward?