If the bat has come into the house and you know without any doubt that no one was bitten or scratched by it, open a window or door and try to steer the bat to the outside. If the bat has come into contact with anyone, you must capture it intact.
If anyone in the house has been in contact with the bat, close the doors to the room the bat is in to keep it contained. Put heavy-duty gloves on, grab a towel and your container with the lid and enter the room.
When the bat roosts, take your container and quickly place it over the bat. Slide the lid under the container, sealing the bat inside. If the bat has not come into contact with anyone, take the container outside and release the bat. However, if the bat has had human contact, place the container in the freezer and call your local public health department to find out the protocol for having the bat tested for rabies.
If the bat roosts on an uneven surface, making it impossible to place the canister over top of it to trap it, throw the towel over the bat and transfer it to a flat surface. Very slowly and carefully release the bat from the towel into the canister. Keep the lid partially over the canister while releasing the bat so that it can be quickly sealed.