Remove obsolete stuff

docs/CLEAR.md

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+Umbraco Cms Clear
+--
+----
+
+Once the solution has been used to run a site, one may want to "reset" the solution in order to run a fresh new site again.
+
+## Fast
+
+At the very minimum, you want
+
+    git clean -Xdf src/Umbraco.Web.UI/App_Data
+    rm src/Umbraco.Web.UI/web.config
+
+Then, a simple 'Rebuild All' in Visual Studio will recreate a fresh `web.config` but should be quite fast (since it does not really need to rebuild anything).
+
+The `clean` Git command force (`-f`) removes (`-X`, note the capital X) all files and directories (`-d`) that are ignored by Git.
+
+This will leave medias and views around, but in most cases, it will be enough.
+
+## More
+
+To perform a more complete clear, you will want to also delete the content of the media, views, masterpages, scripts... directories.
+
+## Full
+
+The following command will force remove all untracked files and directories, be they ignored by Git or not. Combined with `git reset` it can recreate a pristine working directory. 
+
+    git clean -xdf .
+    
+## Docs
+
+See
+* git [clean](<https://git-scm.com/docs/git-clean>)
+* git [reset](<https://git-scm.com/docs/git-reset>)