Another way to kill the M&M (mold and mildew) is to put a teaspoon of bleach and perhaps a cup of water in a spray bottle.
Then, pop the glove box cover off (my '98 comes off without tools), manually open the recirculate door, and spray a couple tablespoons of the mix into the intake with the fan running on high. Do *not* start the engine and run the A/C.
Then let the recirc door close, shut everything off and let it sit overnight. The bleach should kill all the M&M as it spreads around, and using so little, you should have little to no bleach smell; after a while all the bleach evaporates and disspates anyway.
I did mine this way one evening. I used only 10 spritzes or so, and it took care of most of it. I may need to go back in a hit it a second time. The bleach was barely detectable the next afternoon. Personally, I prefer a slight bleach smell to that of M&M.
Fest3er