It has come to my attention that this video was linked to by a popular 3D tutorial site and has since sort of blown up. It also seems that some people are either having a hard time listening to what I say in the video or didn't read the original description. So I'll be clear: THESE ARE NOT THE BEST PRACTICES. THIS IS NOT THE PROPER WORKFLOW FOR CLEANING UP 3D SCAN DATA. This video was not intended for public consumption. A friend of mine asked a very specific question and to answer that question, I rushed through the things he already knew how to do, in the process I did a lot of auto-mapping and auto-retopoing which gives awful results. I thought that was clear in the video but apparently not. It was clear to the intended recipient, but now that this video has received 30k+ views, I apparently have a duty to make it absolutely explicit.
If you've never worked with scan data in ZBrush before, and therefore don't know any better: DON'T DO IT THIS WAY.