Yup, spraying stuff on doesn't work. You can try the caustic soda bomb (I'm still wincing and feel little itchy splotches on my face and hands) or all the stuff you can read about on the internet ranging from Coke to organic lime juice, nothing works. Keep this recipe for when you decide to take the plunge:
1) Get a new seatpost now. Look out for an attractive bargain, buy it and store it.
2) Saw the existing post off 25mm above the frame collar.
3) Remove the hacksaw blade from the saw frame and wrap a cloth around one end. Keep beer on hand and swallow some patience. This is not quick.
4) Have a nice small torch handy.
5) Saw vertically through the remainder of the post stuck inside the frame. The idea is to saw a slot right through the post wall along the length of the post. You will score the frame but be patient, look frequently and adjust your aim as needed.
6) Once you are right through (you'll notice a different colour come through as you nick the frame, take a sip of beer.
7) Now take a pair of standard pliers or one of those hinged pliers (not longnose, you will destroy it) and grip the seat post stubby right next to the slot and wind the post up inwards. By that I mean you open it like an old fashioned sardine can.
8) As soon as the tube bends inwards, pressure is immediately relieved and it will come out in one piece. This seems surprising to most people but remember, it is stuck not through adhesion but through swelling. There is no bond between post and frame.
9) Clean as described above and fit your new post using copper compound or similar.
10) Promise yourself you will remove and check it every six months.
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(No doubt it is a trade secret!)
