How to start fresh Chromium instance?

I am testing web applications. I therefor always need a browser that does not have any cookies, saved logins, etc. Put shortly: a fresh instance.

As we just work with Chromium, I wonder how to start such an fresh instance.

I don't want to set up my regular Chromium installation to not save cookies and such. I want an extra instance.

There is a flag in chromium, which when set starts Chromium with a temporary profile: --temp-profile

I have the following script that I use when I want a clean instance of chromium:

#!/bin/bash
chromium-browser --temp-profile $*

There are two ways to solve that problem:

1. Open a new window in Incognito mode (Ctrl+Shift+N) (thanks to @Salem) for temporary usage
2. Create a new profile with chromium-browser --user-data-dir=/new/directory. In this new profile, you can switch off all cookies, plugins, etc. and restart it with the same command whenever you need it.