You probably know but others might not. Test old lids because after several years, they will not seal properly and you don’t want to get sick. If a jar doesn’t seal, process it again with another lid or put it in the fridge to eat in a few days.
A MUST BUY is the Ball Blue Book https://www.amazon.com/All-Ball-Book-Canning-Preserving/dp/0848746783/ref=sr_1_1?ie=UTF8&qid=1476623882&sr=8-1&keywords=ball+blue+book+of+canning+and+preserving . The rules have changed since the mid 70s so don’t rely on old info. It goes without saying get the print version, not the kindle.
The only person on the internet I’d trust for such, and even then verify with the Ball book, is Susan from https://www.youtube.com/user/imstillworkin . She does her research and explains the hows and whys.
On general cooking, a great how and why book is https://www.amazon.com/Shirley-O-Corriher-Cookwise-Hardcover/dp/B01FMVZPSS/ref=sr_1_4?ie=UTF8&qid=1476624311&sr=8-4&keywords=cookwise+by+shirley+corriher
Thank you!