Among other combinations, an apparatus includes a container having two open ends a gelled mass that includes alcohol and is in contact with an inner wall of the container to provide a seal to prevent air from passing from one of the open ends to the other open end the inner wall being tapered to be narrower at one of the open ends than at the other, broader open end a cover attached at the broader open end and a cover attached at the narrower open end. The gelled mass is in contact with an inner surface of the cover attached at the narrower open end.
