Oh how I HATE Pottery Barn rugs... some of the worst product comes out of their stores - those sisal rugs with stamped on designs that scrub on - hate them. Same with these marshmellow rugs.
Can you post a photo? Is it cotton or wool? If it's cotton, you can use a chlorox mix of one part to 4 water and see if that works. But if it's wool or some other weird fiber, you will have to test some different solutions like Stain Magic for wool, etc.
I always tell clients I can remove the odor but the stains are permanent - and I see if they want the rug washed. Then we get paid for the wash and the odor removal. Sometimes the pet areas get better with the wash (depends on how fresh they are) - then we can play around with stain removal at that point, test an area, and have them say "yes or no" to additional work with that result letting us know the time it will take to get it done.
We do that same thing with flooded rugs - invoice for wash and sanitizing - and after that see if color run removal is possible, test an area, and then do more if it is approved.
Here's why in both cases... when the stain removal - or color run removal - is tied to the wash, and it does not come out as expected, you can end up not being paid for any of the work without a battle. By breaking it up into two phases and making one "standard wash" and the other work "corrective work" you can create more realistic expectations, and a smoother payment cycle.
That's just how we do it... anyway - I'd love a photo if you have one.
Lisa