We will want to turn the nut on one end of the hinge.

Push the hinge completely open, so it's out of the way.

Then take the pliers and turn the last nut slowly counterclockwise (1/6 to 2/6 of a turn should suffice)

Do the same with the other hinge

If you later notice your hinges are too weak to sustain the lid (or still too tight) just work your way back to this step and tighten/loosen them accordingly.