An old boatbuilder's trick for loosening wood screws.
Step 1: Supplies!
You will need:
A stuck wood screw - in this case a smallish, thinnish, bronze slotted flathead screw.
A length of steel rod matching the size of the screw head - I used a 20d nail.
A propane torch.
Vise-grips - 'cause your gonna make that nail HOT.
A screwdriver that fits the screw well.
Step 2: Make Some Hot Metal.
Cut the end of your steel rod square if it isn't already. Avoid using galvanized steel, burning zinc makes nasty fumes.
Heat the end of the rod cherry red.
Step 3: Heat the Screw.
Hold the heated end of the rod against the screw head for thirty seconds or so. Repeat this process two or three more times.
This softens the wood fibers around the screw and also breaks any glue bond.
Step 4: Remove Screw.
Carefully remove screw. There is no need remove it while still hot. It is remarkable how well this works.