Crazy 4 Crabs

How to Give Your Hermit Crab a Bath
When you are looking at your crab, you notice that he hasn't been keeping up with his hygiene. You must give him a bath!
Steps
Fill a large bowl with room temperature dechlorinated water. Make sure it's enough to fully submerge your largest crab.
Put your crab in upside down and let the water fill up his shell, observe that your crab should be able to upright itself. By doing that the dirt and food in its shell should be flushed out. You may repeat one more time if he is very dirty.
Let him walk around in the water for two minutes, then set your hermie in a large container lined with a towel for him to walk on. Usually I would also put in the container shell (freshly boiled in salt water and cooled) for the hermie to change. The hermies are usually very alert and full of energy to shell shop if you put lots of shells in with them.
Some hermie owners bathe their hermies once every two weeks and some do not bath their crabs but provide large water dishes so that their hermies can bathe themselves. When you provide large water dishes, you MUST have pebbles or sponges in it so that the smaller hermie can climb out.
Do not over bathe your hermies or they'll become very stressed.
If your hermie tank have been infested with mites; after cleaning your tank, your hermies will also need a IO bath (salt water bath made with Instant Ocean or any other salt used for marine fish tank).
Make your Instant Ocean water maximum strength (use a hydrometer to measure the salinity to avoid pickled crabs).
After the ocean water bath, bath the hermies in dechlorinated water then let them dry off. But make sure your hermit crab is not sufficating. if you want to dry him off with atowel be extra carefull.

Tips
Know that most crabs will bathe themselves in their waterbowls and don't need a regular bathing. It is starting to be called into question if crabs should be bathed at all. However, you should definitely bathe your crab if you notice mites or other bugs crawling on your crabs.
Dechlorinated water is best made from tap water and Tetra Aqua Brand (or similar) fish water dechlorinator. Simply follow the instructions on the bottle. The gallon-sized jugs from purified water are perfect to keep around for bathing the crabs, and keeping their water bowls full.
Salt water is necessary for your hermit crab's survival. Bathing them in it once in a while will make them feel really good. Use your already dechlorinated fresh water and mix in per package directions, Oceanic Brand Sea Salt, Tropic Marin, and Instant Ocean are good brands.
Your crabs will likely bathe themselves in their waterbowls frequently. Bathe them once a month at most, alternating between fresh and salt water.

Warnings
Make sure the water is room temperature! You don't want to burn the hermit crab. Also, gently put the crab in; don't force it.
Hermit crabs actually store water in their shells to hydrate themselves, and can actually regulate how salty this shell water is. They will use this water to keep their own personal humidity at what they like, they will drink it, or store extra of it when they're about to molt. Bathing your crabs alters this stored water and some are beginning to think that altering it like that could be harmful. If your water dishes aren't deep enough for your crabs to submerge in, maybe have a "water playtime" where you put them in a bigger plastic container that has two deep water bowls in with things to climb in and out from. They can then choose to submerge themselves or not if they don't need it. While they are in this "playtime" plastic tub, you can use the time to clean the tank or make changes to it.
Bathing too much can stress out your hermit crab. Only do it when necessary. It is best to have a bowl already in the hermit crab tank.

Things You'll Need
towel
bowl
hermie hut
dechlorinated fresh or salt water
hermit crab
hermit sponge

Information provided by:

http://www.wikihow.com/Give-Your-Hermit-Crab-a-Bath