If you have metadata set at the root of the site (/ master page), then by default it automatically inherits down through each node in the tree.
Assuming you don't have a ton of metadata setup for pages already, your best bet would be to set the default metadata to empty values. Then go to the pages you want to have empty values or not inherit metadata and uncheck the inherit box. Then go back to the master page and set the metadata to what you had or want it to be.
This will allow you to NOT have to go to each page and manually remove it once you stop inheritance. Another option is to update the content tree via code (not SQL)and set the properties to not inherit and null values.