1) For one kind, soak a pad of cotton or towel in cold or ice water. Squeeze it out so it is wet but not dripping and place it on the injury.
Replace or dip more water onto the pad after a few minutes. Continue cooling area for about 30 minutes or so.
If necessary, keep the compress in place with a bandage. It may be uncomfortable for 2 – 3 minutes but it will help..
2) For the other kind, put crushed ice in a plastic bag. Add a little salt to lower the melting temperature.
Seal the bag and wrap it in a cloth.
Place it on the injury and continue the cooling for 30 minutes or so. And like the above you can keep it in place with a bandage..