[tock172]

Alcohol dripping from a cotton Q-tip around the edges of the button applied liberally over time should help, depending on the severity of the spill, liquid contents and stickiness. I typically opt for the strongest stuff available, 91% isopropyl in my case. I haven't found it to be harmful to any of the plastics in small quantities when I did the same thing to free-up stuck buttons on the steering wheel of my first 135i. However, as I said, I had to repeat the process a few times over a few months for the problem to be solved, along with frequent use of the buttons.