Just a thank you for all your time on my post. Of course I flushed the black tank at the park did add water to the 2 grey tanks like we all do right? I just did not mention, waste of message space. I guess I have been spoiled on my other two R V s never seen this before. But finished winterizing today. I back washed each tank separately while on the 2x8s till they ran clear. I do agree , but no way getting all the crud out, well I do believe its done, But your right if I would have put the cap back on I would never known I was hauling around a bunch of waste all the time. Now I have clean tanks 1 gal anti freeze each tank and everything closed up air tight down below. Least last year the waste tanks had a gallon of anti freeze for company. Thanks again everyone for your time