Sometimes I tried a bunch of containers or images in my own environment, how to remove all the images and containers in the system?
These instructions are provided for your reference:

Note that you do understand what containers and images are in docker.
Do not execute the following commands at will, on the online host:

stop all containers: stop all containers
docker kill $(docker ps -q)

remove all containers: Remove all containers
docker rm $(docker ps -qa)

remove all docker images: remove all docker images
docker rmi $(docker images -q)