Koala, you are still in the summer months, so maybe you can find a place to dry and air it outside too? If so, you could increase the strength of the vinegar to water solution. (Baking soda does draw out smell too...)

I wouldn't leave the mattress in the direct sunlight though. If it is damp from using a solution, you could cover it with a blanket and then put it in the sunlight to dry it quicker.

The vinegar smell might stay for a few days, but it will let up eventually. I've had to use it on my carpets when my babies and animals had accidents, and it's always worked. Try to soak up as much liquid as possible though.

You can buy just a small mattress pad, which shouldn't be too expensive. Try a 2nd hand store with baby fixtures, and bleach it well.

Cherie