Oh my gosh! You stumbled onto quite a treasure!
I do a lot of redwork and here is my take.
I wouldn't wash it. I would spot treat the stains. I did a wall hanging for my SIL and she washed it. Yikes! The DMC floss bled. I was very surprised, so I would assume that the thread in your redwork WILL bleed.
Let us know what you end up doing and please post more pics!