This electric hot water heater was installed four or five years ago.


My first question is about the rust-colored corrosion shown below:
Name:  one.jpg
Views: 135
Size:  53.9 KBName:  1.jpg
Views: 134
Size:  54.6 KBName:  2.jpg
Views: 138
Size:  62.3 KB
Should I use a paste made out of baking soda or something and (try to) scrub this stuff off, or should I contact the landlord, or... ?


Also:
Name:  5.jpg
Views: 142
Size:  34.1 KBName:  9.jpg
Views: 142
Size:  46.1 KB
What would be the best way/materials to keep creepy crawlies (spiders) from entering through these messes left in the wall?


Any help would be greatly appreciated!