Verific

The piece of equipment used to verify an explosive trace detection machine is functioning correctly. Likely to be a liquified chemical substance in the shape of a pen, with airport security staff applying a small amount of substance to a 'clean' swab, in order to check the machines can detect a range of substances.

I need to test the machine on lane 12, has anyone seen the verific?

I'm not sure this verific is working, it's well past its expiration date.