My friend had a painful bloody wound so I'm going to put this rag on it. It's kinda dirty but I don't have anything else.
Wait, you can't use the dirty rag! Why would you risk using a dirty rag on your friend's wound?
I don't really see anything else to use.
If you use a dirty rag, instead of healing the wound it could become infected. You should always use a clean rag if at all possible.
Sometimes the medical stuff is confusing, I usually ignore the complex information and just do the best I can.
I think it would be best if you looked around for something clean to use. I know you're trying to help you friend, and that dirty rag could lead to a dangerous infection.