Back in the shop days I had a stem that none of the above solutions would work for. I cut the stem off, hack sawed it into two pieces and it still would not come out! I took the fork to a machine shop and had to have them machine the stem form the fork. The results were very satisfactory. Given the toxic and corrosive powers of the customers sweat I would hate to be his chamois.
Rick "Spending time in the Wasatch now" Bakke