Vid's guide(s) are a great resource. He has a great depth of knowledge as well as a knack for sharing all of it. He makes things look all easy peasy for someone with no knowledge to try to do. That being said, sometimes it looks too easy. Questions like "Do I need to sand before applying clear coat?" make me wonder how many playfields may be ruined by well intentioned folks who are clueless. Clear can make a playfield look wonderful, but it will only last if the foundation has been laid and every step of the way is done correctly.
Simply wiping some Naphtha on a playfield is probably not going top cut it if the playfield has been subjected to a lot of silicones. Many of the wonder wax products contain silicone or teflon or one of it's slippery cousins.(One of the many reasons that I use only pure carnuba paste wax on my games.) The engineers that designed them worked hard to be able to make a claim of "Lasting up to a year" so a quick swipe with a rag may not actually clean all of the product away.
Let's think of how one would wash a dish or a floor with soap and water. Simply taking some soap on a rag and rubbing a soiled dish or the floor will not clean the dish or the floor. It will just leave a smeared slurry of dirt and soap. You need to follow up with something after loosening the dirt to remove it. Please note that this example is a bit different because dish/household soap is a surfactant which allows the dirt to be carried away by the water. However it is an example that anyone should be able to grasp.
Naphtha, and other silicone and wax removers, are great cleaning agents because they evaporates and leave behind no residue(or residue that does not mix well with clearcoat. However, when it evaporates, what may I ask is left behind???? Not everything is going to be picked up by a tiny piece of dampened cloth when the cloth has already been saturated with cleaning agent.
For my final clean before paint I start with two clean lint free cloths. I spray one with Naphtha or other cleaning agents(there are some water based products that contain much less VOC's). It does not need to be dripping wet, but not too dry. Wipe in one direction only with the damp rag in one hand followed immediately behind it with the dry rag in the other hand. Keep moving to a clean section of cloth and/or change to new cloths often(both wet and dry). Do not wipe back and forth on your final wipe down. Sometimes it may be necessary to scrub back and forth during an initial clean to help your product get into all of the nooks and crannies, but never do so on your final pass.
Pretty flippin long winded post on such a simple task as wiping off a playfield, but I am a firm believer in doing things right and proper prep work is truly key to having a good end product. The shooting of the clear is the easy part. Doing things right is the hard part and that is exactly what Vid tries to show us all of the time.