Do not use isopropyl alcohol or any other solvents for this step. Isopropyl alcohol can damage the coloring and coating of the plastic keys.

Fill the plastic container 3/4 of the way with warm tap water.

Put 2 drops of dish soap into the water filled plastic container.

Place the keycaps in the water and ensure they are fully submerged.

Seal the container with the lid, and let the keycaps sit in the warm water for at least 1 hour.