It might be easy. It's happened to me but I found that after I had flushed and waited and when I thought that's all the liquid that'll come out, I put the cap on. When I took the cap off later on there was a bunch of cr*p that came out. It's just residual liquid still in the pipes. I also smartened up and put an end of line valve on the end of the sewer pipe. No more wet, stinky feet....yes I've broken the handles and just replaced with new ones. They just screw on. Hopefully it's also your problem and nothing more serious.This is the valve at this link...http://www.campingworld.com/shopping/item/twist-on-valve/27868