You can temporarily clear environment variables in the Bash shell on a Linux or Unix-like system by using the following command:
env -i bash --norc --noprofile
This will start a new instance of the Bash shell with a clean environment, without any environment variables set. The -i option specifies that the environment should be cleared, while the --norc and --noprofile options prevent the shell from executing any initialization scripts such as .bashrc and .bash_profile.
To return to your previous environment, simply exit the new shell instance by typing exit.
Note: Clearing the environment can cause some programs and scripts to stop working correctly if they depend on certain environment variables being set. Be careful when using this command, and only use it when necessary.