I agree with Brian......bleach/Chlorox is probably the best anti-microbal agent.
Had to dissinfect the air ducts on the 87 that way.
Heck... a 10% solution of bleach will even kill the HIV virus on contact..its used in some clinics for that purpose.
Cheers,

__________________
FRED

Daily Driver: 98 E300TD 199K
Hobby Car: 69 Austin Mini
Past Diesels: 84 300SD, 312K
87 300SDL, 251K
94 Chev. K-1500 6.5Ltr.TD, 373K