If you are not in a real hurry you can use felt wedges, made from the hammer scraps that the houses sell. Soak these in the wallpaper remover solution and insert one into each mortise. Let them sit there for a while (even as long as a couple hours) re wetting if necessary. You can do other shop work, or even a tuning in the meantime. The most stubborn glue will give up and let go. The old bushings come out fairly easily this way. I hardly ever use steam, but when I do, I use the iron and damp cloth trick. Have you tried the Bushmaster from Pianotek for inserting the new bushings? It really works well.
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