Hello, the main reason is that the fruit skin you put is too wet, and the water has been corroded by bacteria before it dries, leading to mildew. Do you peel the water to get rid of the smell of shoes? I'll give you a way, that is, use used tea leaves to remove water, wrap them in gauze and put them in shoes, and you can see the effect in one day. It is very useful.
I hope it will help you, please adopt it. Thank you.