whats the best way to reglue record covers

Albert, I prefer to use a white PVA adhesive like Elmer's and there's a trick to keeping errant glue from wreaking havoc. Cut a thin sheet of cardboard sized to just barely fit inside the jacket and wrap it with wax paper. Or, you can use silicone release paper like you use to protect a dry mount press platen when you dry mount photographs, it's thicker than wax paper. The non stick surface will protect the inner surfaces from sticking together as the glue dries.

Wow, I can't believe how much time we can spend talking about glue seams! It's no wonder non audiophiles consider us strange. Of course, paper conservers have week long conferences debating this stuff. In any event, Rubber makes a good point about valuable records. Archival glues are far less likely to cause discoloration with the passing years. Contact cements are not archival, although easy to use. PVA (Polyvinyl acetate) glues like Elmer's white and glues designated as archival are not going to cause any problems. Hot glues are also pretty safe too.