I turn off sounds, and when I come back to the game again they are on again for Candy Crush Jelly. I've cleared cache, I've uninstalled and reinstalled and still the sounds are on each time. It is annoying and frustrating that they will not stay off.
I find it the easiest to mute my speakers and headphones on my PC in general; then you don´t need to do anything else like clearing cache or uninstalling and reinstalling.