The workbook for the small group I participated in a few years back had a number of possibilities in the appendices. In one suggestion the leader was invited to bring a bowl of water, towels, soap, and rocks. The stones were supposed to be about the size of an orange. Small enough to hold in your hand but big enough to render that hand incapable of doing anything else.
Each member of the class would take a turn picking up a rock, and identifying it with an old grudge. The time they were not included on a guest list. The cold shoulder they got from a coworker. Or deeper hurts, like an estrangement.
Then the leader would pass the bowl around and invite each participant to scrub their hands. Sudsy water is a universal symbol for cleansing on a spiritual realm as well. But the presence of resentment keeps us inert. Like a rock in our gripped fingers. It turns out that you cannot wash your hands while still clutching the stone.
In the pile of books Ben keeps by his chair is one of amazing animal facts. This morning he told me one.
"When a bee stings someone it is paralyzed!"
"I didn't know that, Ben. Thanks!"
The symbolism struck me. While bees are usually invested in self preservation rather than malevolent intent, we humans are not so inclined.
Wash yourself, make yourself clean, put away the evil of your doings from before my eyes. Cease to do evil, learn to do well. -Isaiah 1