Re: athlete's foot
Once you get athelet's foot, it is an ongoing problem, matter of keeping it under control. Fungus can go dormant and raise it's ugly head on down the road.
There are prescription oral meds on the market that may get rid of fungus, however, it does have possible serious side effects. You have to take one pill a day for a year. I was able to take the med but my son was not, caused an all over headache and other symptoms. Even tho I took the med several years ago, I still get breakouts if my feet get hot/sweaty in closed shoes.
I now have 7 pairs shoes and rotate, only wearing a pair every 7 days. I also spray the inside of shoes with Lysol Spray when I take them off. This helps along with shoes being able to dry for 7 days.
Flip-flops are not the complete answer either since the water splashes fungus from the floor up onto your feet, tho, it is better than nothing. If you are in a swimming pool, wear swim shoes.
How long fungus lives in shoes not worn, I am not sure. It could be dormant and the heat and prespiration could activate it again.
Boiling socks should kill the fungus (use white socks, colored will fade). Won't help that much since shoes will still have fungus. Some people put wet socks in a microwave to kill bacteria/fungus. Not sure how they do that.