So in my search to fine tune _Mathematica_ to what works for me, I found a nice setting that helps separate variable declaration between notebooks. Under Global Preferences, searching for CellContext and changing from "Global'\*" to Notebook does this.  Sweet, but now I am having trouble clearing all the variables.  `ClearAll["Global`\``*"]` no longer works, and so I figured, since that's the setting I changed, maybe it would now be `ClearAll[Notebook]`. However, this doesn't work either and warns that `Notebook` is protected.

Maybe there is a better method of operation instead of the path i'm attempting to go down.  I use _Mathematica_ to do all of my Physics homework in. So between each problem i usually do a `ClearAll` so i'm not contaminating possible variables between problems with wrong values.