How to remove a local Git repo from TortoiseGit?

Don't know about TortoiseGit but the git init command simply creates a (hidden) .git directory in the root of the repository and fills it with some needed files. So to undo an init all you need to do is to delete this .git directory. Note that some files in this directory can be write protected, so a warning dialog can appear. Please also note that all commits you have made in this repository will be lost (which should be no problem in your case).

However I don't know if this works or is enough when using TortoiseGit…