I keep mine wrapped in an old towel and tucked into my drybox. I used to keep it separate in an only kitty little box along with a charcoal starter, tongs, grabber, ove-glove, etc. I got out of that habit when I found I was using the DO for more than just charcoal cooking. You could wrap it in a cloth and stick it in a small drybag as well, just make sure you remove it between trips so the moisture does not sit in it.
The old towel is wearing thin, so I was looking at these, Dutch Oven Case, Outdoor Cookers & Grills, Gsi Outdoors | Campmor
, just this morning thinking that would be a better option than finding another old towel.