Yes, it is possible to put clothes in the dryer without using soap. The primary function of a dryer is to remove moisture from the clothes through the use of heat and airflow. While soap or detergent is typically used in the washing machine to clean clothes, it is not required during the drying process.
When placing clothes in the dryer without soap, it is important to ensure that they are clean and free from any stains or dirt. If you've already washed your clothes and they are ready for drying, you can safely put them in the dryer without adding any additional soap or detergent.
Keep in mind that the dryer does not have cleaning properties, so it won't remove any stains or odors from the clothes. It simply dries them. If your clothes have visible stains or need freshening up, it's best to wash them with soap in the washing machine before transferring them to the dryer.