You can bulk trash your contacts. This archives them and removes them from the basic search.
To trash your contacts, go to CRM → View Contacts.
Perform a search for the contacts you would like to trash. After searching, select the contacts from the result that you would like to trash. If none are selected, it will trash all contacts in the search result. Go to the Actions button, then click Trash All to trash the contacts.
An alert will appear. Click Yes to trash them.
Please note that this process does not completely delete the contacts. Rather, it archives them and removed them from basic searches. You can recover trashed contacts in the advanced tab.