Set Aside
You find some fingers from long ago. They must have been set aside by their previous owners. They definitely weren't cut off or anything, someone just decided they didn't want them anymore and set them aside.
What would have to happen for you to set aside your own fingers? Try to imagine it right now.
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I know why they set aside their fingers long ago, it's because there was no soap (そ). If you didn't have soap to clean your fingers you wouldn't want to keep them for very long...
Think of all the things you do with your fingers. Now picture how they would look if you had never ever cleaned them with soap. Uhg, disgusting. You should just set them aside here, and find some new ones.