Some Keys Of My Keyboard Have Gone Bonkers

I sometimes eat snacks and crumbs fall into the keyboard, it's a habit i find hard to give up. I already ruined a keyboard this way (many keys stopped working) so i try not to eat there. My new keyboard is considerably Crumb-Free.But it has been acting strange lately. One day all of a sudden the "3" and "4" keys on the top (see pics of keys and the type of keyboard i have) stopped working. I took...