Hello and thank you for using Fixya's services.
I have "killed" so many keyboards this way.
If water was spilled there would be some hope but coffee, tea, milk, soda, etc. have sugar which leaks into the chip board and causes static or as you are experiencing "sticking" of the keys.
I can recommend one trick I haven't tried myself but heard it works really well. Placing the keyboard in the dishwasher. I know this sounds strange but it has worked for many. Here are the
instructions if you would like to give it a try.
This method, I have never tried, as I do not have a dishwasher. I usually jump on
eBay and immediately purchase me a new one for under $30.00. Gives me a chance to upgrade every so often.
Hope this helps and please let me know if you have any questions.