How to deal with rude, abusive, or intemperate letters

Norman Geras passes on an example of one strategy for dealing with an unwise or intemperate letter you've written yourself (quoted from here):

Anyone tempted to send a rude letter, or to send an offensive reply to a rude letter, might well follow the example of the late, great Colonel Alfred Wintle, an eccentric and irascible figure who was imprisoned in the Tower of London in 1939 for trying to steal an aircraft with which he intended to invade France, single-handedly. In 1946, Colonel Wintle wrote to The Times from the Cavalry Club: “Sir, I have just written you a long letter. On reading it over, I have thrown it in the wastepaper basket. Hoping this will meet with your approval, I am Sir . . .”

What about responding to overwrought or idiotic letters you receive? I confess that I've always wanted to find the right opportunity to use a snappy comeback I vaguely remember seeing attributed to Mark Twain, or George Bernard Shaw, or someone of that sort. Having received an angry letter from some correspondent, this person responded by writing (more or less):

Dear Sir,

I believe I should warn you that a dangerous lunatic appears to be sending out letters and putting your name on them.

I suppose it would work for e-mail, too. (Not to mention a lot of the stuff that fills up "comments" threads on blogs--except that there the "dangerous lunatic" bit wouldn't always be a joke.)

Update: Sebastien Angel, a once-upon-a-time student of mine at UPenn, wrote me to suggest that this letter-from-a-lunatic response should be attributed to Steven Young, a Democratic US Senator from Ohio from 1958-1971 and a noted political eccentric. Sure enough, a 1962 Time Magazine profile of Young included the following example of the Senator's famously terse and undiplomatic correspondence:

Answering critical mail, he writes: "Some crackpot has written to me and signed your name to the letter. I thought you ought to know about this before it gets any further."

Some other examples:

To one disenchanted supporter he said frankly: "You are entirely misinformed and your letter is silly, but thank you for voting for me." But the classic Young reply remains: "Sir: You are a liar. Sincerely, Stephen M. Young, United States Senator."

Well, I still have the feeling that Sen. Young was paraphrasing an earlier version from the 19th (or early 20th) century. But so far he's the best-authenticated source, and I thank Sebastien for the tip.

Still your humble servant,
Jeff Weintraub