How to perfectly wipe a duplicated project (statistics & URLs & emails) in GSA SER ?

I wanted to duplicate an already used project and couldn’t find out how to clear everything in the new copy. To delete the URL cache, the URL history and the accounts is not enough. The statistics (Submitted/Verified) for example keep the data from the original project. I’m sure there is some more data kept in the background too. Who can help please?