A testing container is described having a vessel with a first end, a second end, and a sidewall extending between the first end and the second end. The first end forms an opening into the vessel. The sidewall has one or more protrusions extending inwardly therefrom. The one or more protrusions form a gap having a width in a range between 2-4 mm, and the one or more protrusions have sufficient strength to withstand lateral pressure of a swab positioned in the gap relative to the one or more protrusions and to remove a head of the swab.
