Replacing the top frame is not hard work, just a pain in the rear. Basically, what I did was to run a long razor between the old trim and the glass, both on the outside and inside of the tank. Then, I pulled off the trim in sections (since it broke easily). I slid my fingers between the frame and glass and peeld it off.
Once the old trim is removed, remove as much of the old silicone as you can. Run a bead of new silicone in the channel of the new trim, press it into place, and then weigh the trim down until it fully cures.
Hope this helps. Let me know if you want me to be more specific or have any more questions. Of course, others may have other suggestions as well.
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