I think you cant do much rather then buying a different type of keyboard. I expirienced this problem on several Notebook and for me it fully depends on the Materials used. For example if i use plastic palmrest i have the same problem as you but on my macbook (iknow its not the same as a deddicated keyboard but still you lay your palms on it) i have no issues at all. On my desksetup i use a low profile keyboard so i can lay my hands on the table which also feels good an doesent end up beaing so dirty.
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