Is it safe to eat unopened jars of food after their sell by date?

in this day and age of ultra super health and safety (sometimes OTT in my opinion) do you think it would be safe to eat unopened gl jars or cans of food 2 - 3 years after their sell by dates...i.e curry pastes, pickled veg etc. anything that would have been packaged and processed using todays high food standard technologies?? haven't tins of food been found dating back to WWII been perfectly edible? reason for Q is that a relative recently died and i found loads of jars of unopened goods which on initial observation look fine but am a bit weary whether or not to cook with them. i dont like wasting food and feel guilty just throwing it all out. your thoughts please! Thank you