Last week I had several responses to my question on a way to remove the hardened tack from the bow. I tried 3 things to soften it. WD40 did no good at all. Simple Green had a modest effect. Degreaser/cleaner turned the tack from hockey puck hard to a condition something like old plumbers putty. Still a major chore, but I managed to clean up the rear bow in about 3 hours time.