How to remove a stuck bike seat post without destroying the post

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For Tools you will need a saw, socket set, drill, wire brush drill bit that inside the post sleeve and a long drill bit extension.
For parts you will need about a foot of stout chain, two quick links, 1/4" #8 steel bolt/washers/nut long enough to go through the seat post, two 1/4" steel bolts/washers/nuts at least 5 1/2" long to hold the 2x4s together at the base and a huge eye bolt and a 8' 2x4 stud. all can be bought at your local hardware store.
Look for a rating of at least 1000lb in all the parts you buy. they are low cost and that way you don't need to worry about things snapping.