You can bulk delete contacts from within your contacts module in your admin area.
From your contact table, you can select the contacts you would like to delete by selecting the tick box on the left side of the contacts table, then select the 3 dot button to proceed to delete those contacts.
You will be prompted to confirm that you are happy to delete these contacts.
Once deleted, contacts will be archived for a further 30 days then permanently deleted. This will anonymise all historical transactions related to this contact. After this point, this action can't be reversed.
Contacts who are administrators, active members or main contacts will not be deleted.