Jeff, over at the Herculodge blog, recently posted that the preset #2 button on his C.Crane CC-Radio 2E had become so sticky, it was almost to the point of not being functional.
One of his readers suggested that he use Deoxit spray to remedy the sticky button and it worked!
Deoxit is amazing stuff and something I suggest any radio enthusiast keep handy. Years ago, I had an Icom IC-735 I thought needed a new power button;I had to press and hold the button for the power to turn on. I searched for a replacement botton for weeks. When I reached out to a friend who is an electronics technician, he suggested that I open the chassis and try spraying the button with Deoxit.
I did, and it worked beautifully.
Deoxit is not the cheapest contact cleaner around, but it is the brand I trust the most. It comes in both a spray and liquid form.
another problem involves the push button itself. There is a little nib on the bottom of it that breaks. on one of my radios i actually removed the button and just press the switch directly by sticking my finger through the hole where the button was.