Just found an old Nokia 6300 in the back of a cupboard, still has the box and instructions, has a battery but no SIM card. If I give it away (or sell it, what do you recommend?) and someone puts a new Sim in it, can they get any of my old information from it? I would probably have put the original Sim in a newer phone when I upgraded, a long time ago !! I am charging it at the moment.
No, the new owner will only be able to see whatever is stored in the phone memory but of course you will make sure it is restored to factory settings before you let it go. That will wipe all your data