Yeah, heating the platters doesn't sound like a good idea to me either, but somehow heating just the slider might make it break the adhesion to the platter, due to thermal expansion. I have a spatula tip for my soldering iron; maybe just touching the slider with it would do the trick. Then again, it might just weld it to the platter. :lol: A plastic caliper might let you grip the slider to dislodge it, or maybe file a notch in a plastic knitting needle to push-pull it to break the tension. idk.
Anyway, let us know what finally worked (or failed) for you.