How do you stop your climbing shoes from smelling so bad?
There are sprays that are used for shoes in general to help reduce/prevent bad smells. Normally, I would spray my shoes after each session. Realistically, though, I forget, so I spray them once a week.
Another method I found that really helps with the smell, but not only that, makes the shoes actually smell good, and makes their insides softer, is putting baby powder in them. There are some powders that are scented, and some that are even made specifically for shoes (which probably won't count as baby powder, but same concept).
I usually put it in my shoes once a week (If I forget then once every 2 weeks), and it usually helps eliminate the bad smells almost completely, especially when I spray the deodorant in them.
Another crucial thing is to air them out. Don't put them in any closed place, not in your bag and not in your car or trunk. I learned from this mistake the worst way. Putting your shoes that are already smelly in a closed place just amplifies the horrible smell. I usually have my shoes clipped to the back of my bag, never closed in anything. And I never leave them in the car, as this again is a closed space. Doing this will cause your shoes to smell bad, but also your car, especially in hotter times like summer.