Clean seashells that have been collected from a beach carefully to remove any sand or animal remains and to prevent odors. The Shell Craft website recommends soaking seashells in a 50-50 mixture of bleach and water overnight. Rinse the seashells carefully to remove any remaining debris left inside. Allow them to dry.
Rub a piece of sandpaper lightly over each area of the plastic planter where you wish to place a seashell. This will create a surface for the glue to bond more effectively.
If you are using a glue gun, heat it until ready. Place a small dot of glue on the seashell, and quickly stick it to the desired area of the planter. Hold in place until the glue has bonded. When using a liquid glue, you will have to hold the shells in place longer. A rubber band or tape can be used for this purpose. Allow all glue to dry.
Place the pot on newspapers outside and spray evenly with clear adhesive to seal the shells.