I've had very good luck with using charcoal briquettes intended for the
barbecue.  I filled a plate full of freshly opened charcoal clumps and
left them in the area for a week or so.  It removed the odor completely.

The problem (oops, everything is now an issue) was a fridge with meat
inside that became unplugged.  It was discovered after a couple of
months when the tenant returned from vacation.  Everything was scrubbed
with the usual products -- Clorox, Lysol, Simple Green -- only to have
an awful odor return after a few days.  The charcoal solved the problem.

Bill Chapman