back in college, we used to fix nail holes with toothpaste... try to
find a color that matches the walls (we got lucky, always white).

They always scare you with the "we'll hold your security deposit if
there is any undocumented alteration or damage to your
apartment/dorm"... they really don't care about nail holes, because
they usually claim that you staind the rug or that you scraped a
countertop anyhow.

The "deposit" is a joke at most colleges, btw... they're gonna keep the
whole damn thing no matter what. The washing machine broke down on
the 5th floor of a friends dorm back in the day, they just decided to
pay for a new one by keeping $10 from everyone's deposit when they
moved out for the summer. it was actually listed as "Laundry equipment
replacement"