To show that sin can be removed.
Equipment: Ink, glass of water, bleach, and an eyedropper.
Procedure: Show the glass of water, and make observations about its purity. Use the eyedropper to drop ink into the water, one drop at a time. Talk about how the water is getting increasingly impure.
Explain that after we are baptized, we are like the clean, pure water. Sin is like the ink, and it makes our spirits become slightly dirty.
Pour bleach into the water, and explain that repentance is like the bleach. If we sincerely repent and replace our sins with good actions, we can become as clean as we were after baptism.