How can I widen the mouth of a gl jug?

I have a gl jug that I like to use as a coin jar for all of my pocket change I bring home at the end of the day. My problem is, I tend to bring home a lot of dollar coins. The dollar coins can't quite fit in the jar, so i have them in a separate container. My question is, does anyone have any suggestions as to how I could widen the mouth of this jug so that the coins will fit? Its the perfect size for a coin jar, and the dollar coins almost fit but are just a tad too big. Thank you!