To keep all my issue kit in good working order (and I use it for it's intended purposes in some pretty sh**ty environments) - in all honesty:
Good old Hot soapy water. I do like using mild dish detergent. Dawn is great. A good firm potato brush helps a lot too. Scrub that gear.
Where the black marks are; that's chemical residue from the brasso - I know it washes off the hands with soap and water, but I dont know about fabrics.
Soak first, may help loosen up the grime.
Good luck. Brad
email (option): niteshade underscore ta at hottymail dot com
