Cellar spiders are generally harmless and can be beneficial in controlling other insect populations in your home. If you don't mind having them around, it's perfectly fine to let them live. However, if you want to reduce their numbers, you can take steps to make your home less attractive to them, such as reducing humidity and sealing up cracks and gaps. If you do need to remove them, it's best to use a vacuum or broom to gently sweep them up and release them outside.