Sometimes it is a good idea to make some sort of presentation to soften them up. It can also help if you tell them something historical/good about the family that they didn't know. This will show how serious you are about your family history and how important it will be to future generations.
I used enlarged copies of photos, biographies and extra info, like who was king or queen at the time.
If you are lucky Gran or whoever will take an interest and then start to correct your notes, without realizing what they're doing. Don't expect older folk to admit to a suicide or illigitimate birth in the family.
Very often they are hiding the things you least expect.
Grand mothers is here in Australia and we know she has all sorts of photos and paper work...but she is a very bitter old lady as most of the family is fighting each other for almost no reason its only that i live over 1000kms away that i didn't get into it all and Ive always stayed neutral
the German is is very well documented.....all the way back to when they came from Denmark my mothers side(Scott's and welsh)is also well documented the Polish side is well....almost nothing!
some of the stories from WWII are grand father(Kazimierz Karl kubiak) was a motorcycle messenger in the Polish army he was captured(funny that) was sent to ausvitz then onto a "prison farm" were the guards use to let him go into town in suit and tie to the local PUB!??.......starts to make me think he was Prussian or half German???
and then Grand mothers Family were happy for them to marry?! after the war....to me this is odd as the Germans and poles hated each other at the time??
so its got me stuffed as to WHY how and was grand father more than"just a pole"