The circular shape can then be cut away, leaving you with a ring of cardboard that can be attached to the top of your jar with its own resealable pouring lid. A hack such as this mason jar lid is ...

If so, consider purchasing the Mason Jar Pour Spouts. You can screw these lids onto your existing Mason jars to neatly pour liquids on through a leak-proof nozzle. Simply wash them and reuse them ...