Sadly the technology that allows us to handle huge volumes of data has one limit - no option to selectively delete data.
We advise to clone and rename campaign so you have a clean start with no test data.
You can then delete your test campaign (change its status) - so it does not distract you.
You may want to apply the same logic for offers if you want to remove test data from them too for any reason.
Should you have any further questions, please contact email@example.com and our team will be happy to assist you. Happy tracking!