I have started cooking veges for Mason to save ...

I have started cooking veges for Mason to save buying so many tins, and am wanting to do some fruit as well. Does it have to be cooked?? I have got some peaches, nectarines, plums which I am not sure if need to be cooked, or could just be mashed? I used to stew apples for Kyah but they are a lot harder than these softer fruits. I have also got some melon which I am guessing would be pretty yuck cooked! Be great if you could tell me what fruits you use and how you prepare them - thanks for the help!