Chosen Solution

made the mistake of shampooing carpet on hardwood floor, using too much shampoo, my floor is stained black and green. My thoughts were to sand off polyurethane, scrub stained areas with wood bleach, restain and re poly the affected areas. Any additional advice would be great.

You’re on the right track based on your thoughts in your question, the only thing I would add is that depending on how big your flooring is, I would consider resurfacing the entire wood floor. Otherwise the formerly stained areas will stand out from the rest of your flooring.