Reddit mentions of Ear Guards MARINES, MMA,UFC,WRESTLING,JUDO,RUGBY

I don't know about the Epsom Salt.

There is a school of thought that there is a predisposition to get cauliflower ear that is genetic. The thickness, structure, and flexibility of your ear cartilage are large indicators in vulnerability to the skin tearing away or the cartilage breaking. I tend to agree based completely on a small sample size (the 2 gyms I train at), but I don't know 100%.

Wear comfortable, low profile head gear and you'll be protected from the impact and shearing forces that encourage cauliflower ear.

EDIT: Here are some low-profile headgear examples (in no particular order):

http://www.amazon.com/Ultra-Guard-Grappling-Wrestling-Jitsu/dp/B005ESOWPW

http://www.amazon.com/Deluxe-Guard-Grappling-Wrestling-Jitsu/dp/B005ESOWLG

http://www.amazon.com/KRUSHCO-WRESTLING-EG-1-Ultra-Earguard-adult/dp/B001HB831O

http://www.amazon.com/Guards-MARINES-WRESTLING-JUDO-RUGBY/dp/B004SI162Q

http://www.amazon.com/Kimurawear-ReActive-Ear-Guards/dp/B00667GIAW

http://www.amazon.com/ProForce-Ultra-Strike-Ear-Guard/dp/B005BV83IO

(Sorry for all of the Amazon links. They just have a bunch of different options "right there".)