Every night when you get home, put ice cold water in a bowl and dip your feet. Don't add hot water.
Fill the bowl and start to put your feet in it.
Leave it for 15 seconds, then wipe your feet with a soft towel and put on warm socks. Do this every night if you want to strengthen your immune system with this speedy manner.
But if you're already have a cold or flu, then do these cold baths on every 4 hours.Plus you can add sea salt for detoxification.
Do not be afraid that you would worse the situation, the ice cold bath can enhance immunity, according to many doctors.