How many times does this needs to be said?
You can not recall Senators or for that matter, Representatives. According to several court rulings on this issue, they are considered federal officials and thus cannot be recalled by their respective states.
Ask yourself this question: why is it that no member of congress has ever been recalled in the entire history of the United States?
Recall in and of itself is only possible in the 18 states that you mentioned, but this only applies to Governors, Mayors, State Senators, Councilmen/women, Assemblymen/women, etc. NOT to Senators or Representatives.
Aside from that, recalls are extremely rare and have happened maybe a dozen or so times in the history of the union, with the most famous recall being that of Gray Davis of California.
So, as much as I’d like to recall every single one of the bastards, I just don’t think it’s possible, legally.
I believe you'll find that not all states fit your assumptions. There are 18 states that allow for recall elections. Now rather it can be accomplished or not is another matter entirely. But what better reason for a recall could their be other than a violation of the US Constitution and a breaking of one's oath of office?