I got my starter a part and now I have a few questions. Not familiar with everything inside. I ordered a rebuild kit which should allow me to rebuild everything at the base attached to the brushes.

1) How should I or Can I clean the inside of the housing? Can I soak it and scrub all the surfaces?
Inside Housing 1
Inside Housing 2

2) Do I need to do anything to this? Should I sand it or scrub it? I plan on sanding the copper end to clean it up but what about the rest(the blue area)?
Pic 1
Pic 2

3) Also the top part of the housing has a hole in it. It does not look like it is a natural part of it. It looks like wear or something ate into it. Should I get this repaired? Can I leave it? or is it supposed to be there? Or do I need to get a new one.
Hole in Starter

4) The contact on the top of the housing has a slight step to it. Shoulp I flatten it or just clean it up?
Starter Contact 1
Starter Contact 2

All Starter Photos
Starter Photos