If you are like me and have lived in numerous hole in the wall houses, then you probably also have perforated their walls. Or your housemates did it for you.
Toothpaste will fill in any little holes for long enough for you to get a recommendation for a new home and make your getaway.
Walls which are heavily pockmarked from knife-throwing practice should be entirely removed. New drywall sections should be placed in the wall with spackle by the housemate who claimed he was handy and knew how to fix drywall (even if he made a terrible hash of it after having denied having any such ability once the time came to actually repair the wall in question.)
Broadsword holes should be plugged with the broadsword in question. This punishes the housemate (or "friend") who got so carried away. Also it strikes fear into the hearts of your landlord's evil minions.
Bullet holes should be plugged by taking photos of your housemates and "friends"
standing next to the bullet holes in question. You may need these pictures
for the ensuing trial.
And be sure to place a plastic Jesus in the wall before plastering over any really deep holes. (I'm not sure why this thing with the plastic Jesus is important, but one of my housemates at the time swore it was.)