Or freeze them..
Might sounds like a crazy idea and always check with the better half first lol.. but chuck smelly boots and gloves in a freezer inside a plastic bag of course.. and leave for at least 48 hours..
Detergent etc will kill and remove the skin cells and sweat secretions that are the food for the bacteria that eat them and cause the smell, but can damage some types of boots.
Freezing them will destroy the bacteria if frozen for sufficiently, but be careful to remove any plastic armamanets/buckles etc you can and don't try flexing them till they have warmed up again or you will get brittle fractures.
A mate has to do this regularly with his kidds cubbley toys as she is majorly alergic to dust mites and asthmatic.
If your boots are ultra smelly, then a possibley a swill out as above and then total dry out and then a freezing might help. I don't recommend trying to freeze them unless you dried them out as water expansion will damage the boots.
Hope that helps..
PS works on smelly gloves a treat..
safe riding and hope to see you out on the road. .. John..