If you're not working with particular clients anymore and there's no need to keep them in your database, you can easily delete them. We have two ways to do it:
Select
CRM > Clients and mark chosen records. From the top bar select trash can icon.
If you want to delete clients from the whole page, mark the main checkbox above clients list and select a trash can icon. This way you can delete clients site by site. To make the proccess faster, set displaying at 100 per page (a cog icon in the top right corner >
Display options):
Click on a chosen client and select
Edit in the top right corner. Next, select
Delete - also in the top right corner.