When placed in the Postman 'Tests' tab, this script will unset all the variables that start with a specifically given prefix so that it's slightly different from the .clear() built-in fuction.

DynamicallyUnsetVariables.js

function cleanup() {
    const clean = _.keys(pm.environment.toObject())
    _.each(clean, (arrItem) => {
        if (arrItem.startsWith("some_prefix")) {
            pm.environment.unset(arrItem)
        }
    })
}
cleanup()

Hello,
But how you set this to run at end of the collection run?
you have a "last request" where after you run the clean variables?

It exists some way to postman knows the end of collection run?

I knew the what the final request was in my Collection so I have in run within there because it worked in my context.

Depends on the way that you structure your own Collections, you could have a folder that contains a request that tearsdown the data following a Collection run.

One of the Postman community members write about how he does this in his own context.

https://community.getpostman.com/t/my-code-snippets-from-the-london-postman-summit-paul-farrell/4591