How do you get rid of hornets that are going into an enclosed area (small openings) outside the house?

Question

You can't see their nests.

Answer 1

"Hornets are far more difficult and dangerous to control than paper wasps. The nests resemble a large, inverted tear-drop shaped ball which typically is attached to a tree, bush or side of a building. Hornet nests may contain thousands of wasps which are extremely aggressive when disturbed. The nests are often located out of reach and removal is best accomplished by a professional pest control firm.

A full wasp suit sealed at the wrists, ankles and collar is recommended when disposing of a hornet nest. Treatment can be accomplished by applying a wasp freeze-type, aerosol insecticide or dust formulation (Sevin, or Ficam,) directly into the nest opening. Hornet nests have a single opening, usually toward the bottom, where the wasps enter and exit. It is essential that the paper envelope of the nest not be broken open during treatment or the irritated wasps will scatter in all directions, causing even greater problems.

Following treatment, wait at least a day before removing the nest to ensure that all of the wasps are killed. If hornets continue to be observed, the application may need to be repeated. Experienced pest control operators will sometimes remove a hornet nest which is attached to a branch by slipping a plastic garbage bag over the intact nest and clipping it at the point of attachment. This technique should not be attempted by anyone else and should only be done at night with a wasp suit. "
http://www.uky.edu/Ag/Entomology/entfacts/struct/ef620.htm

Answer 2

Some good answers here...what I do is duck tape over the holes.

Answer 3

I shoot some wasp killer into the hole, then seal it with a rag, paper or tape...Works all the time

Answer 4

stuff the openings with fine steel wool

Answer 5

find the opening spray foam in it