I'm brand new here @ Craftster, so hello!
I bought a few old army surplus ammo bags at a local surplus store for this recon; each bag cost $2, and each was covered in dirt/sand to the point of absolute stiffness - these things were like boards!
After using a seam ripper to remove some of the outer equipment straps (making the bag smooth on the outside, instead of leaving the excess straps you see in the back view of the original) and detaching the shoulder straps (which simply buckle on already), the bags were given a series of soaks in a strong bleach and salt mixture until they were not only free of dirt, but pliable again! Yay! Canvas again instead of hard as rocks!
After their baths in the bleach/salt mixture, in they went into a stronger water and bleach mix in order to take out the rest of the green color that they originally were. Then, I rinsed them until all the bleach was gone and let them dry out.
The next step? Some good ol' RIT! I used the dark brown, but the canvas was so thick that the fabric only took a light khaki color, which i actually ended up liking better. I reattached the shoulder straps, which I washed but did not bleach - this left me with a khaki bag with an olive green strap, a great contrast.
Next, a trip to Micheal's craft store for a pack of iron-on cherries and an initial, and VOILA! Looks much better, doesn't it? I saved the second bag for whenever some other inspiration strikes me - the first one, completed, gets me a lot of compliments.