In 40 years of messing with tubes, never seen this before

[eleventeen]

Plowing through the enormous pile of hi-fi junk I bought for parts this last weekend, this is a 6AU6 from "the next piece I picked from the pile". Can you see it? Missing pin. When I pulled the tube, pin 5 was left behind in the socket. I have never seen this on a tube that apparently still retains its vacuum.

[Willabe]

Just glue it back in.   

[Paul1453]

Just glue it back in.   

If it were a rare tube that I didn't have any of, I'd probably give that a try Willabe.   

But I already have a big bag of 6AU6s.
I'd bet you do too, Eleventeen.   

[TIMBO]

I had a 12AX7 do that just recently and of course it was old.
I can imagine that lots of years heating and cooling, left on a shelf for another lot of years, bit of corrosion, end of story. Thanks