My 93-year-old neighbor Esther has a butternut tree in her front yard. Butternut is also called "white walnut" (as opposed to "black walnut.")
This year must have been a mast year for the nuts, because Esther said she had thousands of butternuts littering her yard. She filled dozens of containers, and finally gave them away to Martin, who filled the bed of his truck with Esther's butternut harvest.
Martin rakes the nuts onto a concrete pad, covers them with metal roofing, and then runs over them with his tractor to crack the fragrant green shells. Then he shovels that mess into a cement mixer, using a lot of water to wash them all clean. Butternuts are hard nuts to crack.
We ourselves can be a hard nut to crack, especially when we get going on one of our favorite grudges. How do we loosen the shell when we've hardened our heart against someone? Sometimes, life will grind us up until there's nothing left for us to do but let go. Let be.
But more often, we just keep grinding away on our grudge. "He shouldn't have...." "That's not fair." "She should...."
We wash that grudge clean in the water of loving-kindness. Simply rinse your mind with your favorite phrase. "May i feel safe." "May i have ease of well-being." It will take a while. Days perhaps. Or even months.
Simply keep rinsing your mind with loving-kindness until your heart cracks open.