So I was looking into things and have discovered that the smelly boots that some kids wear will be full of bacteria and that this can cause issues with infections on the feet.
Washing them alone doesn't seem to get rid of the smell which means the bacteria is still there.
I have a boot dryer but again the smell will remain.
So having a look around I found this below. It uses UV and helps kill the bacteria.
I know on the past on this community there have been conversations about smelly boots
This is just another idea and product.