I was driving the MINI home yesterday with the aircon on, and that smell started coming out of the vents again. Arrrrgh! That slightly metallic, off-putting scent. Today I was bored, and that's always dangerous. I've tried several things to get whatever it is living in the airbox to die and stay dead. I'd kill it with fire if I could. I've used $10 cans of sterilizing products for car aircons to some effect, but the problem is that one can really only aim it into the blower cage and let the blower sling it around in the airbox. I looked into taking the heater box out and opening it up to scrub it out, but the instructions from the BMW TIS cd include pulling the steering column, the entire dash, the instruments, the center console, and of course draining all coolant and evacuating the Freon (or for the naughty, taking a personal bite of the ozone layer). What I want is a way to send a fine aerosol into the airbox, so that it can settle on everything inside and tear the cellular membranes right off those smelly pests. And, since I have a daughter with asthma, I have a steady supply of "nebulizers" that exist to create aerosol mists. These things cost about $5 new, and they need about 35psi to make a good strong, steady mist. A tiny, tiny air compressor can keep up with one. So, below is nothing more than a medical nebulizer duct-taped to a spare aluminum block, sitting under the air intake for the heater box (with the filter and cover removed from the car). The mist is sucked right into the box. I'm currently sending Febreeze Antimicrobial into the airbox. An anti-fungal agent will be next if necessary. Edit: After doing this for a while, I put the car outside in the sun and left it to idle for twenty minutes with recirc on, max heat, to cook out anything still alive. A thermocouple inserted into the top vent reported 180 degrees F, which should kill anything left. Die, nasty smell, die!