Spanish moss is not really a moss but a bromeliad that grows in the branches of trees. It gets moisture from the air and nutrients from rotting plant matter that settles within the moss and on the tree limbs where it is attached. Spanish moss is prevalent in the humid areas of the southern and southeastern United States. It can cover old oak trees so thickly that the leaves are sometimes hidden. It becomes a pest only if it completely shades the leaves of the trees from sunlight. This rarely happens, however, because it is naturally thinned by high winds during thunderstorms.
Take the Spanish moss you intend to clean and spread it out on a table. Spanish moss pulls apart easily. Use your fingers to pick out any debris such as small branches and leaves and discard.
Fill a five-gallon bucket 3/4 full of water and mix in 2 tbsp. of dish washing soap. Agitate the water to blend the soap into the water. Put the Spanish moss you would like to clean in the bucket of soapy water and be sure it is completely submerged. Only put the amount of Spanish moss in the soapy water that you can move around with your hand and clean. If you pack it too tightly, it cannot get enough soapy water circulating around it to get it clean. Let it soak for three hours and occasionally swirl it around in the soapy water during this time. This is enough time to kill any chiggers or other tiny bugs that might be hiding within the moss.
Take the moss out of the bucket of soapy water and use a strong spray of water to rinse the Spanish moss of any leftover debris and dead bugs.
Spread the cleaned moss on a table in direct sun to dry. If using the same table you used to first clean the moss of debris, clean the table with soapy water and dry to remove any tiny bugs. When the moss is completely dry, store in a plastic bag with ventilation holes or a ventilated box. The dried moss will continue to be slightly supple, because it will still be alive. To keep it alive, you need to moisten it with a mist of water every week and store in a ventilated area where it cannot mildew. Otherwise, it will dry and turn gray but can still be used for crafts.