Be sure your browser window is closed and open up CCcleaner.
Go to the "options" tab and then the "cookies" tab and you will see something similar to the image below.
You will have 2 craig cookies in the left pane. Move the "post" cookie to the right pane to save leave the other where it is as in the above image. don't worry about any other cookies. Only one should be in the right pane on a new user account.
Click the cleaner tab and check the boxes like the below image and then run.
When all done you should be able to go back to "cookies and see only the "post" cookie in the right pane.
You can now close out CCcleaner.
This process should be done every time you log out of craig and close your browser. The "post" cookie will always be saved and the other will be terminated.
This will give you a fresh look each time you login to craig and they will be unable to collect unnecessary info about your account and posting habits. You will be viewed as a small time poster and not a spammer. You are only fooling the bots but this will limit red flags coming up and causing your account to be checked out by an actual moderator.
This will also reduce the phone verification request and ghosting risk associated with multiple posting. This will go a long way to cover up posting outside your geo-area if you wish to do so. You will still need to be judicious about posting so as to keep flagging to a minimum.
There you have it... you have posted your first ad, even though it is a test. After you began posting your real ads you can delete it... no harm done.