My "cure" for pasty butt.
Tools needed: small bowl or jar, warm water, paper towels, q-tips, lubricant (olive oil, veggie oil, Vaseline, k-y jelly), hair dryer (optional), molasses (optional)
Step 1: Put warm water in a small bowl. You want it deep enough for the chicks bottom to be covered with water. Don't make the water too hot or too cold, it needs to be around the same temperature you would wash a human baby in. Let the chick soak for about 5 minutes. Do not leave the chick unattended for ANY reason.
Step 2: Remove the chick from the water and wipe it's rear gently with paper towels, baby wipes, whatever you have. Once the vent is cleared, the chick may poop... A LOT. If it does, wipe that away as well.
Step 3: Finish drying the chick. You can use a hair dryer (be careful not to burn by having the heat too high or too close), more paper towels, whatever. You just want to get the chick as dry as possible.
Step 4: Take a q-tip and use it to apply the lubricant to the vent and the feathers surrounding the vent. This is to help prevent it from recurring.
Step 5 (optional): You can add molasses to the chicks water to prevent it from occurring. I don't know how much as I've not done this myself.