how do you remove the nut on the input jack? no spanner or socket will fit in there!
I assume you just mistyped strat. When I changed mine I first unscrewed the entire piece of metal that holds the jack from the body. Then I just used a pair of pliers to remove the jack itself from the piece that holds it. Let me know if that's what you were looking for.
Haven't you heard?

It's a battle of words
this is kinda funny, cause I always had the problem of that nut coming loose and even had the jack fall into the guitar once on its own. kentris is right tho, the best way to remove (or put back) the jack on a strat and most other guitars is to remove the metal plate that it is mounted to. it should just be two small screws.
I use needle nose pliers to turn the nut
Fact: Bears eat beats. Bears beats Battlestar Galactica.
I have a 1/4" nut driver that I use. You'll still want to remove the jack plate from the body, it's much easier that way.
I Japanese Fenders
MIJ '86 Strat, MIJ '95 Foto Flame Tele, Jackson JSX-94
Schecter C-1 Classic 3TSB, Takamine EG544SC-4C
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Fender Geddy Lee Sig Bass, Ibanez DTT700 Destroyer