I have several Dell Latitude E6520 laptops whose the palmrests became tacky / sticky. This problem also concerns other models sharing the same "rubberized" palmrest coating (E6320, E6420, E6430, E6530, a.s.o.).
On a forum, someone mentioned that this was caused by a degradation of the neopren coating caused by cleaning alcohols (e.g. isopropyl alcohol), at least when not diluted enough. I'm not a chemist and cannot confirm if the exact nature of the surface is neopren, but his answer makes sense to me. At least cleaning does not make the palmrests less tacky.
Some people have tips and tricks to make the palmrest less tacky, like applying wax. I'm not truly convinced by this solution, and wonder if there is some product or family of compounds which, by cold application, would trigger kind of "soft vulcanization" to harden the "ruberrized" coating again and make it more slippery.
Thank you for your indulgence towards my possible jargon mistakes.