2 or 3 heaping Tbsp. Vicks Vapor Rub
1/4 cup baking soda
1/4 cup corn starch
candy mold or mini muffin pan
Melt Vicks in a bowl in the microwave (only took 20 seconds). Add the corn starch and baking soda, then mix with a spoon until it forms a thick paste.
Place into freezer for an hour, then remove by popping them out of the mold with a table knife.
To use lay a shower bomb on the floor of the shower where the water will hit it, but away from where you will be standing or walking. The bombs fill the shower with a nice menthol vapor that helps to ease a stuffy head or cough.
I store my bombs in a labeled zip lock bag in the freezer.