Hi Gcdrag,
Welcome to ECF, glad you made the choice to quit smoking. I never cleaned out my vivis when getting them, I guess if your more comfortable with it, go ahead and take the top and bottom off and rinse under hot water. The vivi nova might be the easiest to clean. When changing flavors or every few day, take the top and bottom off, fill a bowl with the hottest water your tap will provide, remove the head (part with the wick, rinse that under hot water) throw it all in the bowl (head, shaft, tank and upper and lower threads) and let it soak for 10 or so minutes. Then put the head on the shaft (dry off as best you can of course) and dryburn the coils. Dry burning is a way to remove the old juice that has gunked up on the head. So just put the vivi on your twist without the tank and top and hit the button for a second or 2 until you see the coils glow and no longer smell or see smoke from the coils.
Put back together, fill with juice and your good to go. The wicks do take a few mins to wick the juice back into the head.