First and foremost NEVER give your gerbil a water bath. The only time a water bath should be used is if your gerbil has something attached to it's fur that could be potentially fatal (oil, soap, etc). And we highly suggest you take your gerbil to a vet in that situation. So if you're not using water, how do you give a gerbil a bath? With sand! Yep, that's right- sand. But not just any dust. Chinchilla sand. Alright- we'll break this down step by step!
Step One: Get some chinchilla bathing sand. Visit your local pet shop and get a box or bag of chinchilla sand. There is also chinchilla dust- you do not want that. You specifically want sand. Dust can cause respiratory problems in small animals like gerbils.
Step Two: Find the right bathtub. A chinchilla dust pan- which can also be found at your local pet shop works well for a gerbil bath tub. But you can also use a small flower pot on it's side, a shallow 'sandwich' tupperware dish, or even a small children's cereal bowl.
Step Three: Fill the bathtub. You should fill your gerbil's 'bathtub' with two to three inches of sand. This will supply enough for your gerbil to roll around in and possibly accidentally fling some out.
Step Four: Place the sand bath in your gerbil's habitat. When setting the bath in you gerbil's habitat look for an open area where there are no toys, tunnels, or play gyms that could get in your gerbil's way while they are playing in the sand. Also leave it in an area where you can easily remove it and supervise your gerbil while they bathe.
Step Five: Let them inspect. If it is your first time bathing your gerbil, they may be a bit 'bath shy'. Many gerbil's will inspect the bath, but not all will jump in and begin rolling around. Do not force your gerbil to bathe. Rather let them experiment on their own. It may take them a while to learn the right technique, but be patient. If your gerbil doesn't seem interested, remove the bath and try again at a different time. You can inspire them to hop into the new area with a few toys or even a few seeds.
Step Six: Remove after 5 to 10 minutes of bathing. Once your gerbil has begun rolling around, let them 'bathe' for 5 to 10 minutes. After that time remove the bath from your gerbil's habitat. If they bathe too long that can possibly dry out their skin. Gerbil's should only be permitted to bathe two or three times a month.