I have found tying one end to a tree and the other to a four wheel drive usually works. A 5 lb hammer usually works to beat them apart too. Hope this helps. Or try a hair dryer on the outer part to swell it a little if the WD40 doesn't work. Sorry couldn't resist.
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Join the Puget Sound Anglers Sno-King Chapter. Meets second Thursday of every month at the SCS Center, 220 Railroad Ave. Edmonds, WA 98020 at 6:30pm Two buildings south of the Edmonds Ferry on the beach.