You can also use household products for installing nails more permanently in old nail holes.
Why Not to Leave the Holes
Even if the appearance of nail holes in your walls doesn't bother you, nail holes should be filled. Holes in the wall, especially exterior nail holes and those that are located around fixtures, such as windows and doors, can pose more than just an aesthetic problem. According to Washington State University, exterior nail holes can attract insects, including bees to the exterior of your home.
Interior Nail Holes
If the walls of your home are built out of drywall, it’s likely that you have spackling paste or drywall compound on hand. Either of these fillers can be spread over nail holes with a putty knife, using as many coats as necessary until the hole is no longer visible, and then sanded down to level with the wall. If the walls of your home are wood, wood filler or wood putty are alternatives to spackling paste and drywall compound. Whichever of these fillers you have on hand, you can further blend the nail holes into the surrounding wall by painting or staining the filled holes the same color as the original drywall or wood.
Exterior Nail Holes
If you need to fill exterior nail holes, it is best to use a product that creates a waterproof seal with the wall. Caulking, the same type used around plumbing fixtures in your home, is a common household product that meets this need. If you work with cars, you may also have glazing compound at home. Glazing compound can be applied to exterior nail holes just like spackling or drywall. Once you fill the exterior nail hole, paint over it to integrate it into the look of the wall.
When Installing Wall Objects
If you would like to hang an object or install a fixture where an existing wall or fixtures has been, you may need to work with old nail holes. Though you can fill the nail holes prior to installing the new fixtures using the household products outlined above, the filled holes generally are not as sturdy as the older holes. To create a tight grip inside a nail hole that has already been used, use nails anchors or liquid adhesive inside the nail hole before driving the nail into the wall to hold the nail in place.
Common Household Items
Aside from fillers, several common household items can be used to fill nail holes as well. Safe Natural Tips recommends mixing a paste of 1 part cornstarch and 1 part salt with just enough water to allow the mixture to spread, or adding baking soda to glue to thicken the glue into a paste. Another common household filler option is toothpaste, though toothpaste may attract ants.