Sheesh. I switched saddles on my IRO Angus, the new one had a higher profile, and when I went to adjust the seat post I found it totally frozen in the frame. I hadn't adjusted it in I guess close to a year, and have ridden many times in the rain, so all I can figure is that road sand and whatever slowly silted down between the post and frame. I tried squirting silicon down there several times (including when gently flexing open the seat tube with a screwdriver in the slot). I was able to rotate the saddle a little back and forth and so started trying to work everything up and out (standing on one pedal), when I realized I was only separating the head from the stem of the cheap seatpost. I wasn't moving the seatpost at all.

Any recommendations for a super solvent to try working in there, or other suggestions? Seatpost is anodized aluminum, frame is 631.